[InstCombine] Preserve GEP no-wrap flags (#141113)

Author: artagnon

llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp

@@ -537,7 +537,7 @@ Instruction *InstCombinerImpl::visitExtractElementInst(ExtractElementInst &EI) {
 
           GetElementPtrInst *NewGEP = GetElementPtrInst::Create(
               GEP->getSourceElementType(), NewPtr, NewOps);
-          NewGEP->setIsInBounds(GEP->isInBounds());
+          NewGEP->setNoWrapFlags(GEP->getNoWrapFlags());
           return NewGEP;
         }
       }
@@ -1982,7 +1982,7 @@ static Value *buildNew(Instruction *I, ArrayRef<Value*> NewOps,
       ArrayRef<Value*> Idx = NewOps.slice(1);
       return Builder.CreateGEP(cast<GEPOperator>(I)->getSourceElementType(),
                                Ptr, Idx, "",
-                               cast<GEPOperator>(I)->isInBounds());
+                               cast<GEPOperator>(I)->getNoWrapFlags());
     }
   }
   llvm_unreachable("failed to rebuild vector instructions");

llvm/test/Transforms/InstCombine/gep-vector-indices.ll

@@ -12,8 +12,8 @@ define ptr @vector_splat_indices_v2i64_ext0(ptr %a) {
   ret ptr %res
 }
 
-define ptr @vector_splat_indices_nxv2i64_ext0(ptr %a) {
-; CHECK-LABEL: @vector_splat_indices_nxv2i64_ext0(
+define ptr @vector_splat_indices_nxv2i64_ext0_inbounds(ptr %a) {
+; CHECK-LABEL: @vector_splat_indices_nxv2i64_ext0_inbounds(
 ; CHECK-NEXT:    [[RES:%.*]] = getelementptr inbounds nuw i8, ptr [[A:%.*]], i64 16
 ; CHECK-NEXT:    ret ptr [[RES]]
 ;
@@ -24,6 +24,30 @@ define ptr @vector_splat_indices_nxv2i64_ext0(ptr %a) {
   ret ptr %res
 }
 
+define ptr @vector_splat_indices_nxv2i64_ext0_nuw(ptr %a) {
+; CHECK-LABEL: @vector_splat_indices_nxv2i64_ext0_nuw(
+; CHECK-NEXT:    [[RES:%.*]] = getelementptr nuw i8, ptr [[A:%.*]], i64 16
+; CHECK-NEXT:    ret ptr [[RES]]
+;
+  %tmp = insertelement <vscale x 2 x i64> poison, i64 4, i32 0
+  %splatof4 = shufflevector <vscale x 2 x i64> %tmp, <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
+  %gep = getelementptr nuw i32, ptr %a, <vscale x 2 x i64> %splatof4
+  %res = extractelement <vscale x 2 x ptr> %gep, i32 0
+  ret ptr %res
+}
+
+define ptr @vector_splat_indices_nxv2i64_ext0_nusw(ptr %a) {
+; CHECK-LABEL: @vector_splat_indices_nxv2i64_ext0_nusw(
+; CHECK-NEXT:    [[RES:%.*]] = getelementptr nusw nuw i8, ptr [[A:%.*]], i64 16
+; CHECK-NEXT:    ret ptr [[RES]]
+;
+  %tmp = insertelement <vscale x 2 x i64> poison, i64 4, i32 0
+  %splatof4 = shufflevector <vscale x 2 x i64> %tmp, <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
+  %gep = getelementptr nusw i32, ptr %a, <vscale x 2 x i64> %splatof4
+  %res = extractelement <vscale x 2 x ptr> %gep, i32 0
+  ret ptr %res
+}
+
 define ptr @vector_indices_v2i64_ext0(ptr %a, <2 x i64> %indices) {
 ; CHECK-LABEL: @vector_indices_v2i64_ext0(
 ; CHECK-NEXT:    [[TMP1:%.*]] = extractelement <2 x i64> [[INDICES:%.*]], i64 0

llvm/test/Transforms/InstCombine/vec_shuffle.ll

@@ -261,6 +261,45 @@ define <1 x ptr> @shuffle_gep(ptr %x1, ptr %x2) {
   ret <1 x ptr> %ret
 }
 
+define <1 x ptr> @shuffle_gep_inbounds(ptr %x1, ptr %x2) {
+; CHECK-LABEL: @shuffle_gep_inbounds(
+; CHECK-NEXT:    [[TMP1:%.*]] = insertelement <1 x ptr> poison, ptr [[X2:%.*]], i64 0
+; CHECK-NEXT:    [[RET:%.*]] = getelementptr inbounds i8, <1 x ptr> [[TMP1]], i64 5
+; CHECK-NEXT:    ret <1 x ptr> [[RET]]
+;
+  %ins.1 = insertelement <2 x ptr> poison, ptr %x1, i32 0
+  %ins.2 = insertelement <2 x ptr> %ins.1, ptr %x2, i32 1
+  %gep = getelementptr inbounds i8, <2 x ptr> %ins.2, i64 5
+  %ret = shufflevector <2 x ptr> %gep, <2 x ptr> poison, <1 x i32> <i32 1>
+  ret <1 x ptr> %ret
+}
+
+define <1 x ptr> @shuffle_gep_nuw(ptr %x1, ptr %x2) {
+; CHECK-LABEL: @shuffle_gep_nuw(
+; CHECK-NEXT:    [[TMP1:%.*]] = insertelement <1 x ptr> poison, ptr [[X2:%.*]], i64 0
+; CHECK-NEXT:    [[RET:%.*]] = getelementptr nuw i8, <1 x ptr> [[TMP1]], i64 5
+; CHECK-NEXT:    ret <1 x ptr> [[RET]]
+;
+  %ins.1 = insertelement <2 x ptr> poison, ptr %x1, i32 0
+  %ins.2 = insertelement <2 x ptr> %ins.1, ptr %x2, i32 1
+  %gep = getelementptr nuw i8, <2 x ptr> %ins.2, i64 5
+  %ret = shufflevector <2 x ptr> %gep, <2 x ptr> poison, <1 x i32> <i32 1>
+  ret <1 x ptr> %ret
+}
+
+define <1 x ptr> @shuffle_gep_nusw(ptr %x1, ptr %x2) {
+; CHECK-LABEL: @shuffle_gep_nusw(
+; CHECK-NEXT:    [[TMP1:%.*]] = insertelement <1 x ptr> poison, ptr [[X2:%.*]], i64 0
+; CHECK-NEXT:    [[RET:%.*]] = getelementptr nusw i8, <1 x ptr> [[TMP1]], i64 5
+; CHECK-NEXT:    ret <1 x ptr> [[RET]]
+;
+  %ins.1 = insertelement <2 x ptr> poison, ptr %x1, i32 0
+  %ins.2 = insertelement <2 x ptr> %ins.1, ptr %x2, i32 1
+  %gep = getelementptr nusw i8, <2 x ptr> %ins.2, i64 5
+  %ret = shufflevector <2 x ptr> %gep, <2 x ptr> poison, <1 x i32> <i32 1>
+  ret <1 x ptr> %ret
+}
+
 ; Increasing length of vector ops is not a good canonicalization.
 
 define <3 x i32> @add_wider(i32 %y, i32 %z) {