[llvm] becfb46 - [RISCV] Add test for vmerge combine that should be prevented

[Luke Lau via llvm-commits]

Author: Luke Lau
Date: 2023-07-13T11:42:20+01:00
New Revision: becfb4612a3951415ca1a6cfa714fa250605f1a8

URL: https://github.com/llvm/llvm-project/commit/becfb4612a3951415ca1a6cfa714fa250605f1a8
DIFF: https://github.com/llvm/llvm-project/commit/becfb4612a3951415ca1a6cfa714fa250605f1a8.diff

LOG: [RISCV] Add test for vmerge combine that should be prevented

The fadd in these test cases is constrained and may set fflags differently
depending on the active elements (the nofpexcept flag isn't set on the node).
Therefore to preserve semantics we shouldn't change its mask.

Reviewed By: reames

Differential Revision: https://reviews.llvm.org/D154979

Added: 
    

Modified: 
    llvm/test/CodeGen/RISCV/rvv/rvv-peephole-vmerge-vops.ll

Removed: 
    


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diff  --git a/llvm/test/CodeGen/RISCV/rvv/rvv-peephole-vmerge-vops.ll b/llvm/test/CodeGen/RISCV/rvv/rvv-peephole-vmerge-vops.ll
index 1ab039e461c2d6..350bc0100c356f 100644
--- a/llvm/test/CodeGen/RISCV/rvv/rvv-peephole-vmerge-vops.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/rvv-peephole-vmerge-vops.ll
@@ -361,6 +361,36 @@ define <vscale x 2 x float> @vpmerge_fadd(<vscale x 2 x float> %passthru, <vscal
   ret <vscale x 2 x float> %b
 }
 
+; This shouldn't be folded because we need to preserve exceptions with
+; "fpexcept.strict" exception behaviour, and masking may hide them.
+define <vscale x 2 x float> @vpmerge_constrained_fadd(<vscale x 2 x float> %passthru, <vscale x 2 x float> %x, <vscale x 2 x float> %y, <vscale x 2 x i1> %m, i64 %vl) strictfp {
+; CHECK-LABEL: vpmerge_constrained_fadd:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    vsetvli a1, zero, e32, m1, ta, ma
+; CHECK-NEXT:    vfadd.vv v9, v9, v10
+; CHECK-NEXT:    vsetvli zero, a0, e32, m1, tu, ma
+; CHECK-NEXT:    vmerge.vvm v8, v8, v9, v0
+; CHECK-NEXT:    ret
+  %a = call <vscale x 2 x float> @llvm.experimental.constrained.fadd(<vscale x 2 x float> %x, <vscale x 2 x float> %y, metadata !"round.dynamic", metadata !"fpexcept.strict") strictfp
+  %b = call <vscale x 2 x float> @llvm.riscv.vmerge.nxv2f32.nxv2f32(<vscale x 2 x float> %passthru, <vscale x 2 x float> %passthru, <vscale x 2 x float> %a, <vscale x 2 x i1> %m, i64 %vl)
+  ret <vscale x 2 x float> %b
+}
+declare <vscale x 2 x float> @llvm.experimental.constrained.fadd(<vscale x 2 x float>, <vscale x 2 x float>, metadata, metadata)
+declare <vscale x 2 x float> @llvm.riscv.vmerge.nxv2f32.nxv2f32(<vscale x 2 x float>, <vscale x 2 x float>, <vscale x 2 x float>, <vscale x 2 x i1>, i64)
+
+; FIXME: This shouldn't be folded because we need to preserve exceptions with
+; "fpexcept.strict" exception behaviour, and masking may hide them.
+define <vscale x 2 x float> @vpmerge_constrained_fadd_vlmax(<vscale x 2 x float> %passthru, <vscale x 2 x float> %x, <vscale x 2 x float> %y, <vscale x 2 x i1> %m) strictfp {
+; CHECK-LABEL: vpmerge_constrained_fadd_vlmax:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    vsetvli a0, zero, e32, m1, tu, mu
+; CHECK-NEXT:    vfadd.vv v8, v9, v10, v0.t
+; CHECK-NEXT:    ret
+  %a = call <vscale x 2 x float> @llvm.experimental.constrained.fadd(<vscale x 2 x float> %x, <vscale x 2 x float> %y, metadata !"round.dynamic", metadata !"fpexcept.strict") strictfp
+  %b = call <vscale x 2 x float> @llvm.riscv.vmerge.nxv2f32.nxv2f32(<vscale x 2 x float> %passthru, <vscale x 2 x float> %passthru, <vscale x 2 x float> %a, <vscale x 2 x i1> %m, i64 -1)
+  ret <vscale x 2 x float> %b
+}
+
 ; Test conversion by fptosi.
 define <vscale x 2 x i16> @vpmerge_fptosi(<vscale x 2 x i16> %passthru, <vscale x 2 x float> %x, <vscale x 2 x i1> %m, i32 zeroext %vl) {
 ; CHECK-LABEL: vpmerge_fptosi: