[llvm] d4773c6 - [RISCV] Fix a crash in RISCVGatherScatterLowering

[Philip Reames via llvm-commits]

Author: Philip Reames
Date: 2023-04-15T21:27:17-07:00
New Revision: d4773c6a3dfa0da8802bc7adb6e127a36cc0600a

URL: https://github.com/llvm/llvm-project/commit/d4773c6a3dfa0da8802bc7adb6e127a36cc0600a
DIFF: https://github.com/llvm/llvm-project/commit/d4773c6a3dfa0da8802bc7adb6e127a36cc0600a.diff

LOG: [RISCV] Fix a crash in RISCVGatherScatterLowering

We were assuming that the constant must always be fixed length when this is not required.  Such code is unlikely after optimization, which is why we didn't see this previously.

Added: 
    

Modified: 
    llvm/lib/Target/RISCV/RISCVGatherScatterLowering.cpp
    llvm/test/CodeGen/RISCV/rvv/strided-load-store.ll

Removed: 
    


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diff  --git a/llvm/lib/Target/RISCV/RISCVGatherScatterLowering.cpp b/llvm/lib/Target/RISCV/RISCVGatherScatterLowering.cpp
index 7e7b25d43de57..d40ad25e28757 100644
--- a/llvm/lib/Target/RISCV/RISCVGatherScatterLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVGatherScatterLowering.cpp
@@ -107,6 +107,9 @@ bool RISCVGatherScatterLowering::isLegalTypeAndAlignment(Type *DataType,
 
 // TODO: Should we consider the mask when looking for a stride?
 static std::pair<Value *, Value *> matchStridedConstant(Constant *StartC) {
+  if (!isa<FixedVectorType>(StartC->getType()))
+    return std::make_pair(nullptr, nullptr);
+
   unsigned NumElts = cast<FixedVectorType>(StartC->getType())->getNumElements();
 
   // Check that the start value is a strided constant.

diff  --git a/llvm/test/CodeGen/RISCV/rvv/strided-load-store.ll b/llvm/test/CodeGen/RISCV/rvv/strided-load-store.ll
index bcc73e039977a..f5ba1683ef4c7 100644
--- a/llvm/test/CodeGen/RISCV/rvv/strided-load-store.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/strided-load-store.ll
@@ -135,6 +135,23 @@ define void @scatter_loopless(<vscale x 1 x i64> %x, ptr %p, i64 %stride) {
   ret void
 }
 
+; We previously crashed expecting a constant to be fixed length.
+define void @constant_stride(<vscale x 1 x i64> %x, ptr %p, i64 %stride) {
+; CHECK-LABEL: @constant_stride(
+; CHECK-NEXT:    [[PTRS:%.*]] = getelementptr i32, ptr [[P:%.*]], <vscale x 1 x i64> zeroinitializer
+; CHECK-NEXT:    call void @llvm.masked.scatter.nxv1i64.nxv1p0(<vscale x 1 x i64> [[X:%.*]], <vscale x 1 x ptr> [[PTRS]], i32 8, <vscale x 1 x i1> shufflevector (<vscale x 1 x i1> insertelement (<vscale x 1 x i1> poison, i1 true, i64 0), <vscale x 1 x i1> poison, <vscale x 1 x i32> zeroinitializer))
+; CHECK-NEXT:    ret void
+;
+  %ptrs = getelementptr i32, ptr %p, <vscale x 1 x i64> zeroinitializer
+  call void @llvm.masked.scatter.nxv1i64.nxv1p0(
+  <vscale x 1 x i64> %x,
+  <vscale x 1 x ptr> %ptrs,
+  i32 8,
+  <vscale x 1 x i1> shufflevector (<vscale x 1 x i1> insertelement (<vscale x 1 x i1> poison, i1 1, i64 0), <vscale x 1 x i1> poison, <vscale x 1 x i32> zeroinitializer)
+  )
+  ret void
+}
+
 declare i64 @llvm.vscale.i64()
 declare void @llvm.masked.scatter.nxv1i64.nxv1p0(<vscale x 1 x i64>, <vscale x 1 x ptr>, i32, <vscale x 1 x i1>)
 declare <vscale x 1 x i64> @llvm.masked.gather.nxv1i64.nxv1p0(<vscale x 1 x ptr>, i32, <vscale x 1 x i1>, <vscale x 1 x i64>)