| ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py |
| ; RUN: opt < %s -passes=instcombine -S | FileCheck %s |
| |
| ; If we have some pattern that leaves only some low bits set, and then performs |
| ; left-shift of those bits, if none of the bits that are left after the final |
| ; shift are modified by the mask, we can omit the mask. |
| |
| ; There are many variants to this pattern: |
| ; e) ((x << maskNbits) l>> maskNbits) << shiftNbits |
| ; simplify to: |
| ; x << shiftNbits |
| ; iff (shiftNbits-maskNbits) s>= 0 (i.e. shiftNbits u>= maskNbits) |
| |
| ; Simple tests. We don't care about extra uses. |
| |
| declare void @use32(i32) |
| |
| define i32 @t0_basic(i32 %x, i32 %nbits) { |
| ; CHECK-LABEL: @t0_basic( |
| ; CHECK-NEXT: [[T0:%.*]] = shl i32 [[X:%.*]], [[NBITS:%.*]] |
| ; CHECK-NEXT: [[T1:%.*]] = lshr i32 [[T0]], [[NBITS]] |
| ; CHECK-NEXT: call void @use32(i32 [[T0]]) |
| ; CHECK-NEXT: call void @use32(i32 [[T1]]) |
| ; CHECK-NEXT: [[T2:%.*]] = shl i32 [[X]], [[NBITS]] |
| ; CHECK-NEXT: ret i32 [[T2]] |
| ; |
| %t0 = shl i32 %x, %nbits |
| %t1 = lshr i32 %t0, %nbits |
| call void @use32(i32 %t0) |
| call void @use32(i32 %t1) |
| %t2 = shl i32 %t1, %nbits |
| ret i32 %t2 |
| } |
| |
| define i32 @t1_bigger_shift(i32 %x, i32 %nbits) { |
| ; CHECK-LABEL: @t1_bigger_shift( |
| ; CHECK-NEXT: [[T0:%.*]] = shl i32 [[X:%.*]], [[NBITS:%.*]] |
| ; CHECK-NEXT: [[T1:%.*]] = lshr i32 [[T0]], [[NBITS]] |
| ; CHECK-NEXT: [[T2:%.*]] = add i32 [[NBITS]], 1 |
| ; CHECK-NEXT: call void @use32(i32 [[T0]]) |
| ; CHECK-NEXT: call void @use32(i32 [[T1]]) |
| ; CHECK-NEXT: call void @use32(i32 [[T2]]) |
| ; CHECK-NEXT: [[T3:%.*]] = shl i32 [[X]], [[T2]] |
| ; CHECK-NEXT: ret i32 [[T3]] |
| ; |
| %t0 = shl i32 %x, %nbits |
| %t1 = lshr i32 %t0, %nbits |
| %t2 = add i32 %nbits, 1 |
| call void @use32(i32 %t0) |
| call void @use32(i32 %t1) |
| call void @use32(i32 %t2) |
| %t3 = shl i32 %t1, %t2 |
| ret i32 %t3 |
| } |
| |
| ; Vectors |
| |
| declare void @use3xi32(<3 x i32>) |
| |
| define <3 x i32> @t2_vec_splat(<3 x i32> %x, <3 x i32> %nbits) { |
| ; CHECK-LABEL: @t2_vec_splat( |
| ; CHECK-NEXT: [[T0:%.*]] = shl <3 x i32> [[X:%.*]], [[NBITS:%.*]] |
| ; CHECK-NEXT: [[T1:%.*]] = lshr <3 x i32> [[T0]], [[NBITS]] |
| ; CHECK-NEXT: [[T2:%.*]] = add <3 x i32> [[NBITS]], <i32 1, i32 1, i32 1> |
| ; CHECK-NEXT: call void @use3xi32(<3 x i32> [[T0]]) |
| ; CHECK-NEXT: call void @use3xi32(<3 x i32> [[T1]]) |
| ; CHECK-NEXT: call void @use3xi32(<3 x i32> [[T2]]) |
| ; CHECK-NEXT: [[T3:%.*]] = shl <3 x i32> [[X]], [[T2]] |
| ; CHECK-NEXT: ret <3 x i32> [[T3]] |
| ; |
| %t0 = shl <3 x i32> %x, %nbits |
| %t1 = lshr <3 x i32> %t0, %nbits |
| %t2 = add <3 x i32> %nbits, <i32 1, i32 1, i32 1> |
| call void @use3xi32(<3 x i32> %t0) |
| call void @use3xi32(<3 x i32> %t1) |
| call void @use3xi32(<3 x i32> %t2) |
| %t3 = shl <3 x i32> %t1, %t2 |
| ret <3 x i32> %t3 |
| } |
| |
| define <3 x i32> @t3_vec_nonsplat(<3 x i32> %x, <3 x i32> %nbits) { |
| ; CHECK-LABEL: @t3_vec_nonsplat( |
| ; CHECK-NEXT: [[T0:%.*]] = shl <3 x i32> [[X:%.*]], [[NBITS:%.*]] |
| ; CHECK-NEXT: [[T1:%.*]] = lshr <3 x i32> [[T0]], [[NBITS]] |
| ; CHECK-NEXT: [[T2:%.*]] = add <3 x i32> [[NBITS]], <i32 1, i32 0, i32 2> |
| ; CHECK-NEXT: call void @use3xi32(<3 x i32> [[T0]]) |
| ; CHECK-NEXT: call void @use3xi32(<3 x i32> [[T1]]) |
| ; CHECK-NEXT: call void @use3xi32(<3 x i32> [[T2]]) |
| ; CHECK-NEXT: [[T3:%.*]] = shl <3 x i32> [[X]], [[T2]] |
| ; CHECK-NEXT: ret <3 x i32> [[T3]] |
| ; |
| %t0 = shl <3 x i32> %x, %nbits |
| %t1 = lshr <3 x i32> %t0, %nbits |
| %t2 = add <3 x i32> %nbits, <i32 1, i32 0, i32 2> |
| call void @use3xi32(<3 x i32> %t0) |
| call void @use3xi32(<3 x i32> %t1) |
| call void @use3xi32(<3 x i32> %t2) |
| %t3 = shl <3 x i32> %t1, %t2 |
| ret <3 x i32> %t3 |
| } |
| |
| define <3 x i32> @t4_vec_undef(<3 x i32> %x, <3 x i32> %nbits) { |
| ; CHECK-LABEL: @t4_vec_undef( |
| ; CHECK-NEXT: [[T0:%.*]] = shl <3 x i32> [[X:%.*]], [[NBITS:%.*]] |
| ; CHECK-NEXT: [[T1:%.*]] = lshr <3 x i32> [[T0]], [[NBITS]] |
| ; CHECK-NEXT: [[T2:%.*]] = add <3 x i32> [[NBITS]], <i32 1, i32 undef, i32 1> |
| ; CHECK-NEXT: call void @use3xi32(<3 x i32> [[T0]]) |
| ; CHECK-NEXT: call void @use3xi32(<3 x i32> [[T1]]) |
| ; CHECK-NEXT: call void @use3xi32(<3 x i32> [[T2]]) |
| ; CHECK-NEXT: [[T3:%.*]] = shl <3 x i32> [[X]], [[T2]] |
| ; CHECK-NEXT: ret <3 x i32> [[T3]] |
| ; |
| %t0 = shl <3 x i32> %x, %nbits |
| %t1 = lshr <3 x i32> %t0, %nbits |
| %t2 = add <3 x i32> %nbits, <i32 1, i32 undef, i32 1> |
| call void @use3xi32(<3 x i32> %t0) |
| call void @use3xi32(<3 x i32> %t1) |
| call void @use3xi32(<3 x i32> %t2) |
| %t3 = shl <3 x i32> %t1, %t2 |
| ret <3 x i32> %t3 |
| } |
| |
| ; Fast-math flags. We must not preserve them! |
| |
| define i32 @t5_nuw(i32 %x, i32 %nbits) { |
| ; CHECK-LABEL: @t5_nuw( |
| ; CHECK-NEXT: [[T0:%.*]] = shl i32 [[X:%.*]], [[NBITS:%.*]] |
| ; CHECK-NEXT: [[T1:%.*]] = lshr i32 [[T0]], [[NBITS]] |
| ; CHECK-NEXT: call void @use32(i32 [[T0]]) |
| ; CHECK-NEXT: call void @use32(i32 [[T1]]) |
| ; CHECK-NEXT: [[T2:%.*]] = shl i32 [[X]], [[NBITS]] |
| ; CHECK-NEXT: ret i32 [[T2]] |
| ; |
| %t0 = shl i32 %x, %nbits |
| %t1 = lshr i32 %t0, %nbits |
| call void @use32(i32 %t0) |
| call void @use32(i32 %t1) |
| %t2 = shl nuw i32 %t1, %nbits |
| ret i32 %t2 |
| } |
| |
| define i32 @t6_nsw(i32 %x, i32 %nbits) { |
| ; CHECK-LABEL: @t6_nsw( |
| ; CHECK-NEXT: [[T0:%.*]] = shl i32 [[X:%.*]], [[NBITS:%.*]] |
| ; CHECK-NEXT: [[T1:%.*]] = lshr i32 [[T0]], [[NBITS]] |
| ; CHECK-NEXT: call void @use32(i32 [[T0]]) |
| ; CHECK-NEXT: call void @use32(i32 [[T1]]) |
| ; CHECK-NEXT: [[T2:%.*]] = shl i32 [[X]], [[NBITS]] |
| ; CHECK-NEXT: ret i32 [[T2]] |
| ; |
| %t0 = shl i32 %x, %nbits |
| %t1 = lshr i32 %t0, %nbits |
| call void @use32(i32 %t0) |
| call void @use32(i32 %t1) |
| %t2 = shl nsw i32 %t1, %nbits |
| ret i32 %t2 |
| } |
| |
| define i32 @t7_nuw_nsw(i32 %x, i32 %nbits) { |
| ; CHECK-LABEL: @t7_nuw_nsw( |
| ; CHECK-NEXT: [[T0:%.*]] = shl i32 [[X:%.*]], [[NBITS:%.*]] |
| ; CHECK-NEXT: [[T1:%.*]] = lshr i32 [[T0]], [[NBITS]] |
| ; CHECK-NEXT: call void @use32(i32 [[T0]]) |
| ; CHECK-NEXT: call void @use32(i32 [[T1]]) |
| ; CHECK-NEXT: [[T2:%.*]] = shl i32 [[X]], [[NBITS]] |
| ; CHECK-NEXT: ret i32 [[T2]] |
| ; |
| %t0 = shl i32 %x, %nbits |
| %t1 = lshr i32 %t0, %nbits |
| call void @use32(i32 %t0) |
| call void @use32(i32 %t1) |
| %t2 = shl nuw nsw i32 %t1, %nbits |
| ret i32 %t2 |
| } |
| |
| ; Special test |
| |
| declare void @llvm.assume(i1 %cond) |
| |
| ; We can't simplify (%shiftnbits-%masknbits) but we have an assumption. |
| define i32 @t8_assume_uge(i32 %x, i32 %masknbits, i32 %shiftnbits) { |
| ; CHECK-LABEL: @t8_assume_uge( |
| ; CHECK-NEXT: [[CMP:%.*]] = icmp uge i32 [[SHIFTNBITS:%.*]], [[MASKNBITS:%.*]] |
| ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) |
| ; CHECK-NEXT: [[T0:%.*]] = shl i32 [[X:%.*]], [[MASKNBITS]] |
| ; CHECK-NEXT: [[T1:%.*]] = lshr i32 [[T0]], [[MASKNBITS]] |
| ; CHECK-NEXT: call void @use32(i32 [[T0]]) |
| ; CHECK-NEXT: call void @use32(i32 [[T1]]) |
| ; CHECK-NEXT: [[T2:%.*]] = shl i32 [[T1]], [[SHIFTNBITS]] |
| ; CHECK-NEXT: ret i32 [[T2]] |
| ; |
| %cmp = icmp uge i32 %shiftnbits, %masknbits |
| call void @llvm.assume(i1 %cmp) |
| %t0 = shl i32 %x, %masknbits |
| %t1 = lshr i32 %t0, %masknbits |
| call void @use32(i32 %t0) |
| call void @use32(i32 %t1) |
| %t2 = shl i32 %t1, %shiftnbits |
| ret i32 %t2 |
| } |
| |
| ; Negative tests |
| |
| define i32 @n9_different_shamts0(i32 %x, i32 %nbits0, i32 %nbits1) { |
| ; CHECK-LABEL: @n9_different_shamts0( |
| ; CHECK-NEXT: [[T0:%.*]] = shl i32 [[X:%.*]], [[NBITS0:%.*]] |
| ; CHECK-NEXT: [[T1:%.*]] = lshr i32 [[T0]], [[NBITS1:%.*]] |
| ; CHECK-NEXT: call void @use32(i32 [[T0]]) |
| ; CHECK-NEXT: call void @use32(i32 [[T1]]) |
| ; CHECK-NEXT: [[T2:%.*]] = shl i32 [[T1]], [[NBITS0]] |
| ; CHECK-NEXT: ret i32 [[T2]] |
| ; |
| %t0 = shl i32 %x, %nbits0 ; different shift amts |
| %t1 = lshr i32 %t0, %nbits1 ; different shift amts |
| call void @use32(i32 %t0) |
| call void @use32(i32 %t1) |
| %t2 = shl i32 %t1, %nbits0 |
| ret i32 %t2 |
| } |
| |
| define i32 @n10_different_shamts1(i32 %x, i32 %nbits0, i32 %nbits1) { |
| ; CHECK-LABEL: @n10_different_shamts1( |
| ; CHECK-NEXT: [[T0:%.*]] = shl i32 [[X:%.*]], [[NBITS0:%.*]] |
| ; CHECK-NEXT: [[T1:%.*]] = lshr i32 [[T0]], [[NBITS1:%.*]] |
| ; CHECK-NEXT: call void @use32(i32 [[T0]]) |
| ; CHECK-NEXT: call void @use32(i32 [[T1]]) |
| ; CHECK-NEXT: [[T2:%.*]] = shl i32 [[T1]], [[NBITS1]] |
| ; CHECK-NEXT: ret i32 [[T2]] |
| ; |
| %t0 = shl i32 %x, %nbits0 ; different shift amts |
| %t1 = lshr i32 %t0, %nbits1 ; different shift amts |
| call void @use32(i32 %t0) |
| call void @use32(i32 %t1) |
| %t2 = shl i32 %t1, %nbits1 |
| ret i32 %t2 |
| } |