[llvm-branch-commits] [llvm] release/19.x: [x86] combineMUL - when looking for a vector multiply by splat constant, ensure we're only accepting ConstantInt splat scalars. (PR #111246)

[via llvm-branch-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-x86

Author: None (llvmbot)

<details>
<summary>Changes</summary>

Backport 9459d729d22b7bfedad9d3a4237162077c6984a4

Requested by: @<!-- -->RKSimon

---
Full diff: https://github.com/llvm/llvm-project/pull/111246.diff


2 Files Affected:

- (modified) llvm/lib/Target/X86/X86ISelLowering.cpp (+2-1) 
- (added) llvm/test/CodeGen/X86/pr111170.ll (+33) 


``````````diff
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 45989bcd07d37e..71730070c2a5b5 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -47893,7 +47893,8 @@ static SDValue combineMul(SDNode *N, SelectionDAG &DAG,
     if (VT.isVector())
       if (auto *RawC = getTargetConstantFromNode(N->getOperand(1)))
         if (auto *SplatC = RawC->getSplatValue())
-          C = &(SplatC->getUniqueInteger());
+          if (auto *SplatCI = dyn_cast<ConstantInt>(SplatC))
+            C = &(SplatCI->getValue());
 
     if (!C || C->getBitWidth() != VT.getScalarSizeInBits())
       return SDValue();
diff --git a/llvm/test/CodeGen/X86/pr111170.ll b/llvm/test/CodeGen/X86/pr111170.ll
new file mode 100644
index 00000000000000..145bf7119edcb9
--- /dev/null
+++ b/llvm/test/CodeGen/X86/pr111170.ll
@@ -0,0 +1,33 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc < %s -mtriple=i686-pc-windows-msvc -mcpu=corei7-avx | FileCheck %s
+
+define void @PR111170(<16 x i32> %x_load, ptr %offsetsPtr.i) {
+; CHECK-LABEL: PR111170:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    movl {{[0-9]+}}(%esp), %eax
+; CHECK-NEXT:    vbroadcastss {{.*#+}} xmm2 = [2.80259693E-44,2.80259693E-44,2.80259693E-44,2.80259693E-44]
+; CHECK-NEXT:    vpmulld %xmm2, %xmm1, %xmm3
+; CHECK-NEXT:    vextractf128 $1, %ymm1, %xmm1
+; CHECK-NEXT:    vpmulld %xmm2, %xmm1, %xmm1
+; CHECK-NEXT:    vpmulld %xmm2, %xmm0, %xmm4
+; CHECK-NEXT:    vextractf128 $1, %ymm0, %xmm0
+; CHECK-NEXT:    vpmulld %xmm2, %xmm0, %xmm0
+; CHECK-NEXT:    vmovdqu %xmm0, 16(%eax)
+; CHECK-NEXT:    vmovdqu %xmm4, (%eax)
+; CHECK-NEXT:    vmovdqu %xmm1, 48(%eax)
+; CHECK-NEXT:    vmovdqu %xmm3, 32(%eax)
+; CHECK-NEXT:    vpxor %xmm0, %xmm0, %xmm0
+; CHECK-NEXT:    vmovdqu %xmm0, 16
+; CHECK-NEXT:    vmovdqu %xmm0, 0
+; CHECK-NEXT:    vmovdqu %xmm0, 48
+; CHECK-NEXT:    vmovdqu %xmm0, 32
+; CHECK-NEXT:    vzeroupper
+; CHECK-NEXT:    retl
+  %mul__x_load = mul <16 x i32> <i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20>, %x_load
+  store <16 x i32> %mul__x_load, ptr %offsetsPtr.i, align 4
+  %blend1.i12.i = call <8 x float> @llvm.x86.avx.blendv.ps.256(<8 x float> zeroinitializer, <8 x float> <float 0x36E4000000000000, float 0x36E4000000000000, float 0x36E4000000000000, float 0x36E4000000000000, float 0x36E4000000000000, float 0x36E4000000000000, float 0x36E4000000000000, float 0x36E4000000000000>, <8 x float> zeroinitializer)
+  %blend.i13.i = shufflevector <8 x float> zeroinitializer, <8 x float> %blend1.i12.i, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
+  %blendAsInt.i14.i = bitcast <16 x float> %blend.i13.i to <16 x i32>
+  store <16 x i32> %blendAsInt.i14.i, ptr null, align 4
+  ret void
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/111246