[IR] Generate poison for all-poison scalable shufflevector mask

nikic · nikic · commit db9e9eabb783 · 2024-06-24T16:56:02.000+02:00
Ultimately doesn't matter because the bitcode reader interprets
undef and poison interchangeably in this context.
diff --git a/llvm/lib/IR/Instructions.cpp b/llvm/lib/IR/Instructions.cpp
@@ -1822,7 +1822,7 @@ Constant *ShuffleVectorInst::convertShuffleMaskForBitcode(ArrayRef<int> Mask,
     Type *VecTy = VectorType::get(Int32Ty, Mask.size(), true);
     if (Mask[0] == 0)
       return Constant::getNullValue(VecTy);
-    return UndefValue::get(VecTy);
+    return PoisonValue::get(VecTy);
   }
   SmallVector<Constant *, 16> MaskConst;
   for (int Elem : Mask) {

Original file line number	Diff line number	Diff line change
`@@ -1822,7 +1822,7 @@ Constant *ShuffleVectorInst::convertShuffleMaskForBitcode(ArrayRef<int> Mask,`
`1822`	`1822`	`Type *VecTy = VectorType::get(Int32Ty, Mask.size(), true);`
`1823`	`1823`	`if (Mask[0] == 0)`
`1824`	`1824`	`return Constant::getNullValue(VecTy);`
`1825`		`- return UndefValue::get(VecTy);`
	`1825`	`+ return PoisonValue::get(VecTy);`
`1826`	`1826`	`}`
`1827`	`1827`	`SmallVector<Constant *, 16> MaskConst;`
`1828`	`1828`	`for (int Elem : Mask) {`