| ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6 | |
| ; RUN: llc -mtriple=amdgpu6.00 < %s | FileCheck -check-prefix=GFX6 %s | |
| ; RUN: llc -mtriple=amdgpu11.00 < %s | FileCheck -check-prefix=GFX11 %s | |
| declare i32 @llvm.ctlz.i32(i32, i1) | |
| declare i64 @llvm.ctlz.i64(i64, i1) | |
| declare i32 @llvm.amdgcn.sffbh.i32(i32) | |
| declare i32 @llvm.umin.i32(i32, i32) | |
| ; Test that ctls(x) is lowered to umin(ffbh_i32(x), bitwidth) - 1 | |
| ; ctls is formed by the DAG combiner from: ctlz(x ^ ashr(x, 31)) - 1 | |
| define i32 @ctls_i32(i32 %x) { | |
| ; GFX6-LABEL: ctls_i32: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_ffbh_i32_e32 v0, v0 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -1, v0 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: ctls_i32: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_cls_i32_e32 v0, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -1, v0 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %a = ashr i32 %x, 31 | |
| %b = xor i32 %x, %a | |
| %c = call i32 @llvm.ctlz.i32(i32 %b, i1 false) | |
| %d = sub i32 %c, 1 | |
| ret i32 %d | |
| } | |
| define i32 @ctls_i32_known_positive(i32 %x) { | |
| ; GFX6-LABEL: ctls_i32_known_positive: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_and_b32_e32 v0, 0x7fffffff, v0 | |
| ; GFX6-NEXT: v_ffbh_i32_e32 v0, v0 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -1, v0 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: ctls_i32_known_positive: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_and_b32_e32 v0, 0x7fffffff, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_cls_i32_e32 v0, v0 | |
| ; GFX11-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -1, v0 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %pos = and i32 %x, 2147483647 | |
| %a = ashr i32 %pos, 31 | |
| %b = xor i32 %pos, %a | |
| %c = call i32 @llvm.ctlz.i32(i32 %b, i1 false) | |
| %d = sub i32 %c, 1 | |
| ret i32 %d | |
| } | |
| ; sub(ctlz(xor(x, sra(x, 31))), 1) -> ctls(x) | |
| define i32 @ctls_i32_xor_commuted(i32 %x) { | |
| ; GFX6-LABEL: ctls_i32_xor_commuted: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_ffbh_i32_e32 v0, v0 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -1, v0 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: ctls_i32_xor_commuted: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_cls_i32_e32 v0, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -1, v0 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %a = ashr i32 %x, 31 | |
| %b = xor i32 %a, %x ; note: reversed order compared to ctls_i32 | |
| %c = call i32 @llvm.ctlz.i32(i32 %b, i1 false) | |
| %d = sub i32 %c, 1 | |
| ret i32 %d | |
| } | |
| define i32 @ctls_i32_zero_poison(i32 %x) { | |
| ; GFX6-LABEL: ctls_i32_zero_poison: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_ffbh_i32_e32 v0, v0 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -1, v0 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: ctls_i32_zero_poison: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_cls_i32_e32 v0, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -1, v0 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %a = ashr i32 %x, 31 | |
| %b = xor i32 %x, %a | |
| %c = call i32 @llvm.ctlz.i32(i32 %b, i1 true) ; zero_poison = true | |
| %d = sub i32 %c, 1 | |
| ret i32 %d | |
| } | |
| ; umin(ffbh_i32(x), 32) -> ffbh_i32(x). | |
| define i32 @ctls_i32_known_mixed_bits(i32 %x) { | |
| ; GFX6-LABEL: ctls_i32_known_mixed_bits: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_or_b32_e32 v0, 1, v0 | |
| ; GFX6-NEXT: v_and_b32_e32 v0, 0x7fffffff, v0 | |
| ; GFX6-NEXT: v_ffbh_i32_e32 v0, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -1, v0 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: ctls_i32_known_mixed_bits: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_or_b32_e32 v0, 1, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_and_b32_e32 v0, 0x7fffffff, v0 | |
| ; GFX11-NEXT: v_cls_i32_e32 v0, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -1, v0 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| ; Force bit 31 = 0 and bit 0 = 1, so value is neither all-0s nor all-1s | |
| %cleared = and i32 %x, 2147483647 ; clear bit 31 | |
| %mixed = or i32 %cleared, 1 ; set bit 0 | |
| %a = ashr i32 %mixed, 31 | |
| %b = xor i32 %mixed, %a | |
| %c = call i32 @llvm.ctlz.i32(i32 %b, i1 false) | |
| %d = sub i32 %c, 1 | |
| ret i32 %d | |
| } | |
| ; Only bit 0 is known set; the high bits are unknown so x may be all-ones. | |
| ; The umin clamp must be preserved (sffbh(-1) = -1 must clamp to bitwidth). | |
| define i32 @ctls_i32_maybe_all_ones(i32 %x) { | |
| ; GFX6-LABEL: ctls_i32_maybe_all_ones: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_or_b32_e32 v0, 1, v0 | |
| ; GFX6-NEXT: v_ffbh_i32_e32 v0, v0 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: ctls_i32_maybe_all_ones: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_or_b32_e32 v0, 1, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_cls_i32_e32 v0, v0 | |
| ; GFX11-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %nz = or i32 %x, 1 | |
| %sffbh = call i32 @llvm.amdgcn.sffbh.i32(i32 %nz) | |
| %r = call i32 @llvm.umin.i32(i32 %sffbh, i32 32) | |
| ret i32 %r | |
| } | |
| ; test for i64 CTLS. | |
| define i32 @ctls_i64(i64 %x) { | |
| ; GFX6-LABEL: ctls_i64: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_ashrrev_i32_e32 v2, 31, v1 | |
| ; GFX6-NEXT: v_xor_b32_e32 v0, v0, v2 | |
| ; GFX6-NEXT: v_ffbh_u32_e32 v0, v0 | |
| ; GFX6-NEXT: v_xor_b32_e32 v1, v1, v2 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 0xffffffdf, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, 32, v0 | |
| ; GFX6-NEXT: v_ffbh_u32_e32 v1, v1 | |
| ; GFX6-NEXT: v_min3_u32 v0, v0, v1, 64 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -1, v0 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: ctls_i64: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_ashrrev_i32_e32 v2, 31, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(SKIP_1) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_xor_b32_e32 v0, v0, v2 | |
| ; GFX11-NEXT: v_xor_b32_e32 v1, v1, v2 | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v0, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v1, v1 | |
| ; GFX11-NEXT: v_add_nc_u32_e64 v0, v0, 32 clamp | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_min3_u32 v0, v0, v1, 64 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -1, v0 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %a = ashr i64 %x, 63 | |
| %b = xor i64 %x, %a | |
| %c = call i64 @llvm.ctlz.i64(i64 %b, i1 false) | |
| %d = sub i64 %c, 1 | |
| %e = trunc i64 %d to i32 | |
| ret i32 %e | |
| } | |
| ; i16 CTLS via the sub(ctlz(xor(x, sra(x, 15))), 1) pattern. | |
| declare i16 @llvm.ctlz.i16(i16, i1) | |
| define i16 @ctls_i16(i16 %x) { | |
| ; GFX6-LABEL: ctls_i16: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_bfe_i32 v0, v0, 0, 16 | |
| ; GFX6-NEXT: v_ffbh_i32_e32 v0, v0 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX6-NEXT: v_subrev_i32_e32 v0, vcc, 17, v0 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: ctls_i16: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_ashrrev_i16 v0.h, 15, v0.l | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_xor_b16 v0.l, v0.l, v0.h | |
| ; GFX11-NEXT: v_cvt_u32_u16_e32 v0, v0.l | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v0, v0 | |
| ; GFX11-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -16, v0 | |
| ; GFX11-NEXT: v_add_nc_u16 v0.l, v0.l, -1 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %a = ashr i16 %x, 15 | |
| %b = xor i16 %x, %a | |
| %c = call i16 @llvm.ctlz.i16(i16 %b, i1 false) | |
| %d = sub i16 %c, 1 | |
| ret i16 %d | |
| } | |
| ; uniform input should use scalar sffbh. | |
| define amdgpu_ps i32 @ctls_i32_salu(i32 inreg %x) { | |
| ; GFX6-LABEL: ctls_i32_salu: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_flbit_i32 s0, s0 | |
| ; GFX6-NEXT: s_min_u32 s0, s0, 32 | |
| ; GFX6-NEXT: s_add_i32 s0, s0, -1 | |
| ; GFX6-NEXT: ; return to shader part epilog | |
| ; | |
| ; GFX11-LABEL: ctls_i32_salu: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_cls_i32 s0, s0 | |
| ; GFX11-NEXT: s_delay_alu instid0(SALU_CYCLE_1) | instskip(NEXT) | instid1(SALU_CYCLE_1) | |
| ; GFX11-NEXT: s_min_u32 s0, s0, 32 | |
| ; GFX11-NEXT: s_add_i32 s0, s0, -1 | |
| ; GFX11-NEXT: ; return to shader part epilog | |
| %a = ashr i32 %x, 31 | |
| %b = xor i32 %x, %a | |
| %c = call i32 @llvm.ctlz.i32(i32 %b, i1 false) | |
| %d = sub i32 %c, 1 | |
| ret i32 %d | |
| } | |
| define <2 x i32> @ctls_v2i32(<2 x i32> %x) { | |
| ; GFX6-LABEL: ctls_v2i32: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_ashrrev_i32_e32 v2, 31, v1 | |
| ; GFX6-NEXT: v_ashrrev_i32_e32 v3, 31, v0 | |
| ; GFX6-NEXT: v_xor_b32_e32 v1, v1, v2 | |
| ; GFX6-NEXT: v_xor_b32_e32 v0, v0, v3 | |
| ; GFX6-NEXT: v_ffbh_u32_e32 v1, v1 | |
| ; GFX6-NEXT: v_ffbh_u32_e32 v0, v0 | |
| ; GFX6-NEXT: v_min_u32_e32 v1, 32, v1 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -1, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v1, vcc, -1, v1 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: ctls_v2i32: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_ashrrev_i32_e32 v2, 31, v0 | |
| ; GFX11-NEXT: v_ashrrev_i32_e32 v3, 31, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_xor_b32_e32 v0, v0, v2 | |
| ; GFX11-NEXT: v_xor_b32_e32 v1, v1, v3 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v0, v0 | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v1, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX11-NEXT: v_min_u32_e32 v1, 32, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -1, v0 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v1, -1, v1 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %a = ashr <2 x i32> %x, <i32 31, i32 31> | |
| %b = xor <2 x i32> %x, %a | |
| %c = call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> %b, i1 false) | |
| %d = sub <2 x i32> %c, <i32 1, i32 1> | |
| ret <2 x i32> %d | |
| } | |
| declare <2 x i32> @llvm.ctlz.v2i32(<2 x i32>, i1) | |
| declare <4 x i32> @llvm.ctlz.v4i32(<4 x i32>, i1) | |
| define <4 x i32> @ctls_v4i32(<4 x i32> %x) { | |
| ; GFX6-LABEL: ctls_v4i32: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_ffbh_i32_e32 v0, v0 | |
| ; GFX6-NEXT: v_ffbh_i32_e32 v1, v1 | |
| ; GFX6-NEXT: v_ffbh_i32_e32 v2, v2 | |
| ; GFX6-NEXT: v_ffbh_i32_e32 v3, v3 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX6-NEXT: v_min_u32_e32 v1, 32, v1 | |
| ; GFX6-NEXT: v_min_u32_e32 v2, 32, v2 | |
| ; GFX6-NEXT: v_min_u32_e32 v3, 32, v3 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -1, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v1, vcc, -1, v1 | |
| ; GFX6-NEXT: v_add_i32_e32 v2, vcc, -1, v2 | |
| ; GFX6-NEXT: v_add_i32_e32 v3, vcc, -1, v3 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: ctls_v4i32: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_cls_i32_e32 v0, v0 | |
| ; GFX11-NEXT: v_cls_i32_e32 v1, v1 | |
| ; GFX11-NEXT: v_cls_i32_e32 v2, v2 | |
| ; GFX11-NEXT: v_cls_i32_e32 v3, v3 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_4) | instskip(NEXT) | instid1(VALU_DEP_4) | |
| ; GFX11-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX11-NEXT: v_min_u32_e32 v1, 32, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_4) | instskip(NEXT) | instid1(VALU_DEP_4) | |
| ; GFX11-NEXT: v_min_u32_e32 v2, 32, v2 | |
| ; GFX11-NEXT: v_min_u32_e32 v3, 32, v3 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_4) | instskip(NEXT) | instid1(VALU_DEP_4) | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -1, v0 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v1, -1, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_4) | instskip(NEXT) | instid1(VALU_DEP_4) | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v2, -1, v2 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v3, -1, v3 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %a = ashr <4 x i32> %x, <i32 31, i32 31, i32 31, i32 31> | |
| %b = xor <4 x i32> %x, %a | |
| %c = call <4 x i32> @llvm.ctlz.v4i32(<4 x i32> %b, i1 false) | |
| %d = sub <4 x i32> %c, <i32 1, i32 1, i32 1, i32 1> | |
| ret <4 x i32> %d | |
| } | |
| ; umin should be folded away per element per element. | |
| define <2 x i32> @ctls_v2i32_known_mixed_bits(<2 x i32> %x) { | |
| ; GFX6-LABEL: ctls_v2i32_known_mixed_bits: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_or_b32_e32 v1, 1, v1 | |
| ; GFX6-NEXT: v_or_b32_e32 v0, 1, v0 | |
| ; GFX6-NEXT: v_and_b32_e32 v1, 0x7fffffff, v1 | |
| ; GFX6-NEXT: v_and_b32_e32 v0, 0x7fffffff, v0 | |
| ; GFX6-NEXT: v_ffbh_u32_e32 v1, v1 | |
| ; GFX6-NEXT: v_ffbh_u32_e32 v0, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -1, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v1, vcc, -1, v1 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: ctls_v2i32_known_mixed_bits: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_or_b32_e32 v0, 1, v0 | |
| ; GFX11-NEXT: v_or_b32_e32 v1, 1, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_and_b32_e32 v0, 0x7fffffff, v0 | |
| ; GFX11-NEXT: v_and_b32_e32 v1, 0x7fffffff, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v0, v0 | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v1, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -1, v0 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v1, -1, v1 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %cleared = and <2 x i32> %x, <i32 2147483647, i32 2147483647> | |
| %mixed = or <2 x i32> %cleared, <i32 1, i32 1> | |
| %a = ashr <2 x i32> %mixed, <i32 31, i32 31> | |
| %b = xor <2 x i32> %mixed, %a | |
| %c = call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> %b, i1 false) | |
| %d = sub <2 x i32> %c, <i32 1, i32 1> | |
| ret <2 x i32> %d | |
| } | |
| ; Vector with ctlz_zero_poison. | |
| define <2 x i32> @ctls_v2i32_zero_poison(<2 x i32> %x) { | |
| ; GFX6-LABEL: ctls_v2i32_zero_poison: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_ashrrev_i32_e32 v2, 31, v1 | |
| ; GFX6-NEXT: v_ashrrev_i32_e32 v3, 31, v0 | |
| ; GFX6-NEXT: v_xor_b32_e32 v1, v1, v2 | |
| ; GFX6-NEXT: v_xor_b32_e32 v0, v0, v3 | |
| ; GFX6-NEXT: v_ffbh_u32_e32 v1, v1 | |
| ; GFX6-NEXT: v_ffbh_u32_e32 v0, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -1, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v1, vcc, -1, v1 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: ctls_v2i32_zero_poison: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_ashrrev_i32_e32 v2, 31, v0 | |
| ; GFX11-NEXT: v_ashrrev_i32_e32 v3, 31, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_xor_b32_e32 v0, v0, v2 | |
| ; GFX11-NEXT: v_xor_b32_e32 v1, v1, v3 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v0, v0 | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v1, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -1, v0 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v1, -1, v1 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %a = ashr <2 x i32> %x, <i32 31, i32 31> | |
| %b = xor <2 x i32> %x, %a | |
| %c = call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> %b, i1 true) | |
| %d = sub <2 x i32> %c, <i32 1, i32 1> | |
| ret <2 x i32> %d | |
| } | |
| ; Vector commuted XOR operands. | |
| define <2 x i32> @ctls_v2i32_xor_commuted(<2 x i32> %x) { | |
| ; GFX6-LABEL: ctls_v2i32_xor_commuted: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_ashrrev_i32_e32 v2, 31, v1 | |
| ; GFX6-NEXT: v_ashrrev_i32_e32 v3, 31, v0 | |
| ; GFX6-NEXT: v_xor_b32_e32 v1, v2, v1 | |
| ; GFX6-NEXT: v_xor_b32_e32 v0, v3, v0 | |
| ; GFX6-NEXT: v_ffbh_u32_e32 v1, v1 | |
| ; GFX6-NEXT: v_ffbh_u32_e32 v0, v0 | |
| ; GFX6-NEXT: v_min_u32_e32 v1, 32, v1 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -1, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v1, vcc, -1, v1 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: ctls_v2i32_xor_commuted: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_ashrrev_i32_e32 v2, 31, v0 | |
| ; GFX11-NEXT: v_ashrrev_i32_e32 v3, 31, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_xor_b32_e32 v0, v2, v0 | |
| ; GFX11-NEXT: v_xor_b32_e32 v1, v3, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v0, v0 | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v1, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX11-NEXT: v_min_u32_e32 v1, 32, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -1, v0 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v1, -1, v1 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %a = ashr <2 x i32> %x, <i32 31, i32 31> | |
| %b = xor <2 x i32> %a, %x | |
| %c = call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> %b, i1 false) | |
| %d = sub <2 x i32> %c, <i32 1, i32 1> | |
| ret <2 x i32> %d | |
| } | |
| ; Vector known positive: umin should NOT be folded. | |
| define <2 x i32> @ctls_v2i32_known_positive(<2 x i32> %x) { | |
| ; GFX6-LABEL: ctls_v2i32_known_positive: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_and_b32_e32 v1, 0x7fffffff, v1 | |
| ; GFX6-NEXT: v_and_b32_e32 v0, 0x7fffffff, v0 | |
| ; GFX6-NEXT: v_ffbh_u32_e32 v1, v1 | |
| ; GFX6-NEXT: v_ffbh_u32_e32 v0, v0 | |
| ; GFX6-NEXT: v_min_u32_e32 v1, 32, v1 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -1, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v1, vcc, -1, v1 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: ctls_v2i32_known_positive: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_and_b32_e32 v0, 0x7fffffff, v0 | |
| ; GFX11-NEXT: v_and_b32_e32 v1, 0x7fffffff, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v0, v0 | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v1, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX11-NEXT: v_min_u32_e32 v1, 32, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -1, v0 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v1, -1, v1 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %pos = and <2 x i32> %x, <i32 2147483647, i32 2147483647> | |
| %a = ashr <2 x i32> %pos, <i32 31, i32 31> | |
| %b = xor <2 x i32> %pos, %a | |
| %c = call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> %b, i1 false) | |
| %d = sub <2 x i32> %c, <i32 1, i32 1> | |
| ret <2 x i32> %d | |
| } | |
| ; @llvm.amdgcn.sffbh must still produce raw hardware result. | |
| define i32 @sffbh_intrinsic(i32 %x) { | |
| ; GFX6-LABEL: sffbh_intrinsic: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_ffbh_i32_e32 v0, v0 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: sffbh_intrinsic: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_cls_i32_e32 v0, v0 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %r = call i32 @llvm.amdgcn.sffbh.i32(i32 %x) | |
| ret i32 %r | |
| } | |
| ; sitofp i64 to f32 uses sffbh(Hi)-1, not CTLS. | |
| define float @sitofp_i64_to_f32(i64 %x) { | |
| ; GFX6-LABEL: sitofp_i64_to_f32: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_xor_b32_e32 v2, v0, v1 | |
| ; GFX6-NEXT: v_ashrrev_i32_e32 v2, 31, v2 | |
| ; GFX6-NEXT: v_ffbh_i32_e32 v3, v1 | |
| ; GFX6-NEXT: v_add_i32_e32 v2, vcc, 32, v2 | |
| ; GFX6-NEXT: v_add_i32_e32 v3, vcc, -1, v3 | |
| ; GFX6-NEXT: v_min_u32_e32 v2, v3, v2 | |
| ; GFX6-NEXT: v_lshl_b64 v[0:1], v[0:1], v2 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 1, v0 | |
| ; GFX6-NEXT: v_or_b32_e32 v0, v1, v0 | |
| ; GFX6-NEXT: v_cvt_f32_i32_e32 v0, v0 | |
| ; GFX6-NEXT: v_sub_i32_e32 v1, vcc, 32, v2 | |
| ; GFX6-NEXT: v_ldexp_f32_e32 v0, v0, v1 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: sitofp_i64_to_f32: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_xor_b32_e32 v2, v0, v1 | |
| ; GFX11-NEXT: v_cls_i32_e32 v3, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_ashrrev_i32_e32 v2, 31, v2 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v3, -1, v3 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v2, 32, v2 | |
| ; GFX11-NEXT: v_min_u32_e32 v2, v3, v2 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_lshlrev_b64 v[0:1], v2, v[0:1] | |
| ; GFX11-NEXT: v_min_u32_e32 v0, 1, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(SKIP_1) | instid1(VALU_DEP_2) | |
| ; GFX11-NEXT: v_or_b32_e32 v0, v1, v0 | |
| ; GFX11-NEXT: v_sub_nc_u32_e32 v1, 32, v2 | |
| ; GFX11-NEXT: v_cvt_f32_i32_e32 v0, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | |
| ; GFX11-NEXT: v_ldexp_f32 v0, v0, v1 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %r = sitofp i64 %x to float | |
| ret float %r | |
| } | |
| ; Negative tests: | |
| define i32 @no_ctls_wrong_shift(i32 %x) { | |
| ; GFX6-LABEL: no_ctls_wrong_shift: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_ashrrev_i32_e32 v1, 30, v0 | |
| ; GFX6-NEXT: v_xor_b32_e32 v0, v0, v1 | |
| ; GFX6-NEXT: v_ffbh_u32_e32 v0, v0 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -1, v0 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: no_ctls_wrong_shift: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_ashrrev_i32_e32 v1, 30, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_xor_b32_e32 v0, v0, v1 | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v0, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -1, v0 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %a = ashr i32 %x, 30 | |
| %b = xor i32 %x, %a | |
| %c = call i32 @llvm.ctlz.i32(i32 %b, i1 false) | |
| %d = sub i32 %c, 1 | |
| ret i32 %d | |
| } | |
| define i32 @no_ctls_xor_different_value(i32 %x, i32 %y) { | |
| ; GFX6-LABEL: no_ctls_xor_different_value: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_ashrrev_i32_e32 v1, 31, v1 | |
| ; GFX6-NEXT: v_xor_b32_e32 v0, v0, v1 | |
| ; GFX6-NEXT: v_ffbh_u32_e32 v0, v0 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -1, v0 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: no_ctls_xor_different_value: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_ashrrev_i32_e32 v1, 31, v1 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_xor_b32_e32 v0, v0, v1 | |
| ; GFX11-NEXT: v_clz_i32_u32_e32 v0, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -1, v0 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %a = ashr i32 %y, 31 | |
| %b = xor i32 %x, %a | |
| %c = call i32 @llvm.ctlz.i32(i32 %b, i1 false) | |
| %d = sub i32 %c, 1 | |
| ret i32 %d | |
| } | |
| define i32 @no_ctls_sub_2(i32 %x) { | |
| ; GFX6-LABEL: no_ctls_sub_2: | |
| ; GFX6: ; %bb.0: | |
| ; GFX6-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX6-NEXT: v_ffbh_i32_e32 v0, v0 | |
| ; GFX6-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX6-NEXT: v_add_i32_e32 v0, vcc, -2, v0 | |
| ; GFX6-NEXT: s_setpc_b64 s[30:31] | |
| ; | |
| ; GFX11-LABEL: no_ctls_sub_2: | |
| ; GFX11: ; %bb.0: | |
| ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) | |
| ; GFX11-NEXT: v_cls_i32_e32 v0, v0 | |
| ; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1) | |
| ; GFX11-NEXT: v_min_u32_e32 v0, 32, v0 | |
| ; GFX11-NEXT: v_add_nc_u32_e32 v0, -2, v0 | |
| ; GFX11-NEXT: s_setpc_b64 s[30:31] | |
| %a = ashr i32 %x, 31 | |
| %b = xor i32 %x, %a | |
| %c = call i32 @llvm.ctlz.i32(i32 %b, i1 false) | |
| %d = sub i32 %c, 2 | |
| ret i32 %d | |
| } |