[RISCV][VLOPT] Support v[f]slide1up.v{x,f} (#146716)
Similarly to #146710, for vslide1ups vl only determines the destination
elements written to so we can safely reduce their AVL.
We cannot do this for vslide1downs as the vl determines which lane the
new element is to be inserted in, so some negative tests have been
added.diff --git a/llvm/lib/Target/RISCV/RISCVVLOptimizer.cpp b/llvm/lib/Target/RISCV/RISCVVLOptimizer.cpp
index 8402a41..1dd12ab 100644
--- a/llvm/lib/Target/RISCV/RISCVVLOptimizer.cpp
+++ b/llvm/lib/Target/RISCV/RISCVVLOptimizer.cpp
@@ -1045,7 +1045,8 @@
case RISCV::VSLIDEUP_VI:
case RISCV::VSLIDEDOWN_VX:
case RISCV::VSLIDEDOWN_VI:
- // TODO: Handle v[f]slide1up, but not v[f]slide1down.
+ case RISCV::VSLIDE1UP_VX:
+ case RISCV::VFSLIDE1UP_VF:
// Vector Single-Width Floating-Point Add/Subtract Instructions
case RISCV::VFADD_VF:
case RISCV::VFADD_VV:
diff --git a/llvm/test/CodeGen/RISCV/rvv/vl-opt-instrs.ll b/llvm/test/CodeGen/RISCV/rvv/vl-opt-instrs.ll
index f84eebe..e6407b32 100644
--- a/llvm/test/CodeGen/RISCV/rvv/vl-opt-instrs.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/vl-opt-instrs.ll
@@ -3514,6 +3514,92 @@
ret <vscale x 4 x i32> %2
}
+define <vscale x 4 x i32> @vslide1up_vx(<vscale x 4 x i32> %a, iXLen %b, iXLen %vl) {
+; NOVLOPT-LABEL: vslide1up_vx:
+; NOVLOPT: # %bb.0:
+; NOVLOPT-NEXT: vsetvli a2, zero, e32, m2, ta, ma
+; NOVLOPT-NEXT: vslide1up.vx v10, v8, a0
+; NOVLOPT-NEXT: vsetvli zero, a1, e32, m2, ta, ma
+; NOVLOPT-NEXT: vadd.vv v8, v10, v10
+; NOVLOPT-NEXT: ret
+;
+; VLOPT-LABEL: vslide1up_vx:
+; VLOPT: # %bb.0:
+; VLOPT-NEXT: vsetvli zero, a1, e32, m2, ta, ma
+; VLOPT-NEXT: vslide1up.vx v10, v8, a0
+; VLOPT-NEXT: vadd.vv v8, v10, v10
+; VLOPT-NEXT: ret
+ %1 = call <vscale x 4 x i32> @llvm.riscv.vslide1up(<vscale x 4 x i32> poison, <vscale x 4 x i32> %a, iXLen %b, iXLen -1)
+ %2 = call <vscale x 4 x i32> @llvm.riscv.vadd(<vscale x 4 x i32> poison, <vscale x 4 x i32> %1, <vscale x 4 x i32> %1, iXLen %vl)
+ ret <vscale x 4 x i32> %2
+}
+
+define <vscale x 4 x float> @vfslide1up_vf(<vscale x 4 x float> %a, float %b, iXLen %vl) {
+; NOVLOPT-LABEL: vfslide1up_vf:
+; NOVLOPT: # %bb.0:
+; NOVLOPT-NEXT: vsetvli a1, zero, e32, m2, ta, ma
+; NOVLOPT-NEXT: vfslide1up.vf v10, v8, fa0
+; NOVLOPT-NEXT: vsetvli zero, a0, e32, m2, ta, ma
+; NOVLOPT-NEXT: vfadd.vv v8, v10, v10
+; NOVLOPT-NEXT: ret
+;
+; VLOPT-LABEL: vfslide1up_vf:
+; VLOPT: # %bb.0:
+; VLOPT-NEXT: vsetvli zero, a0, e32, m2, ta, ma
+; VLOPT-NEXT: vfslide1up.vf v10, v8, fa0
+; VLOPT-NEXT: vfadd.vv v8, v10, v10
+; VLOPT-NEXT: ret
+ %1 = call <vscale x 4 x float> @llvm.riscv.vfslide1up(<vscale x 4 x float> poison, <vscale x 4 x float> %a, float %b, iXLen -1)
+ %2 = call <vscale x 4 x float> @llvm.riscv.vfadd(<vscale x 4 x float> poison, <vscale x 4 x float> %1, <vscale x 4 x float> %1, iXLen 7, iXLen %vl)
+ ret <vscale x 4 x float> %2
+}
+
+; Negative test – not safe to reduce vl
+
+define <vscale x 4 x i32> @vslide1down_vx(<vscale x 4 x i32> %a, iXLen %b, iXLen %vl) {
+; NOVLOPT-LABEL: vslide1down_vx:
+; NOVLOPT: # %bb.0:
+; NOVLOPT-NEXT: vsetvli a2, zero, e32, m2, ta, ma
+; NOVLOPT-NEXT: vslide1down.vx v8, v8, a0
+; NOVLOPT-NEXT: vsetvli zero, a1, e32, m2, ta, ma
+; NOVLOPT-NEXT: vadd.vv v8, v8, v8
+; NOVLOPT-NEXT: ret
+;
+; VLOPT-LABEL: vslide1down_vx:
+; VLOPT: # %bb.0:
+; VLOPT-NEXT: vsetvli a2, zero, e32, m2, ta, ma
+; VLOPT-NEXT: vslide1down.vx v8, v8, a0
+; VLOPT-NEXT: vsetvli zero, a1, e32, m2, ta, ma
+; VLOPT-NEXT: vadd.vv v8, v8, v8
+; VLOPT-NEXT: ret
+ %1 = call <vscale x 4 x i32> @llvm.riscv.vslide1down(<vscale x 4 x i32> poison, <vscale x 4 x i32> %a, iXLen %b, iXLen -1)
+ %2 = call <vscale x 4 x i32> @llvm.riscv.vadd(<vscale x 4 x i32> poison, <vscale x 4 x i32> %1, <vscale x 4 x i32> %1, iXLen %vl)
+ ret <vscale x 4 x i32> %2
+}
+
+; Negative test – not safe to reduce vl
+
+define <vscale x 4 x float> @vfslide1down_vf(<vscale x 4 x float> %a, float %b, iXLen %vl) {
+; NOVLOPT-LABEL: vfslide1down_vf:
+; NOVLOPT: # %bb.0:
+; NOVLOPT-NEXT: vsetvli a1, zero, e32, m2, ta, ma
+; NOVLOPT-NEXT: vfslide1down.vf v8, v8, fa0
+; NOVLOPT-NEXT: vsetvli zero, a0, e32, m2, ta, ma
+; NOVLOPT-NEXT: vfadd.vv v8, v8, v8
+; NOVLOPT-NEXT: ret
+;
+; VLOPT-LABEL: vfslide1down_vf:
+; VLOPT: # %bb.0:
+; VLOPT-NEXT: vsetvli a1, zero, e32, m2, ta, ma
+; VLOPT-NEXT: vfslide1down.vf v8, v8, fa0
+; VLOPT-NEXT: vsetvli zero, a0, e32, m2, ta, ma
+; VLOPT-NEXT: vfadd.vv v8, v8, v8
+; VLOPT-NEXT: ret
+ %1 = call <vscale x 4 x float> @llvm.riscv.vfslide1down(<vscale x 4 x float> poison, <vscale x 4 x float> %a, float %b, iXLen -1)
+ %2 = call <vscale x 4 x float> @llvm.riscv.vfadd(<vscale x 4 x float> poison, <vscale x 4 x float> %1, <vscale x 4 x float> %1, iXLen 7, iXLen %vl)
+ ret <vscale x 4 x float> %2
+}
+
define <vscale x 4 x float> @vfadd_vv(<vscale x 4 x float> %a, <vscale x 4 x float> %b, iXLen %vl) {
; NOVLOPT-LABEL: vfadd_vv:
; NOVLOPT: # %bb.0:
