[llvm] 60984f5 - [InstCombine] Preserve all gep flags in gep of exact div fold

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2024-06-19T14:33:43+02:00
New Revision: 60984f5be90d3f0378d739792adbd4c5e3dcc0e2

URL: https://github.com/llvm/llvm-project/commit/60984f5be90d3f0378d739792adbd4c5e3dcc0e2
DIFF: https://github.com/llvm/llvm-project/commit/60984f5be90d3f0378d739792adbd4c5e3dcc0e2.diff

LOG: [InstCombine] Preserve all gep flags in gep of exact div fold

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
    llvm/test/Transforms/InstCombine/getelementptr.ll

Removed: 
    


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diff  --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index d926b1f3f568f..a9c994f8076b2 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2941,10 +2941,9 @@ Instruction *InstCombinerImpl::visitGetElementPtrInst(GetElementPtrInst &GEP) {
                                  m_SpecificInt(countr_zero(TyAllocSize)))))) ||
             match(GEP.getOperand(1),
                   m_Exact(m_IDiv(m_Value(V), m_SpecificInt(TyAllocSize))))) {
-          GetElementPtrInst *NewGEP = GetElementPtrInst::Create(
-              Builder.getInt8Ty(), GEP.getPointerOperand(), V);
-          NewGEP->setIsInBounds(GEP.isInBounds());
-          return NewGEP;
+          return GetElementPtrInst::Create(Builder.getInt8Ty(),
+                                           GEP.getPointerOperand(), V,
+                                           GEP.getNoWrapFlags());
         }
       }
     }

diff  --git a/llvm/test/Transforms/InstCombine/getelementptr.ll b/llvm/test/Transforms/InstCombine/getelementptr.ll
index a842484c25a86..722ced1f6abb1 100644
--- a/llvm/test/Transforms/InstCombine/getelementptr.ll
+++ b/llvm/test/Transforms/InstCombine/getelementptr.ll
@@ -1566,6 +1566,16 @@ define ptr @gep_sdiv_inbounds(ptr %p, i64 %off) {
   ret ptr %ptr
 }
 
+define ptr @gep_sdiv_nuw(ptr %p, i64 %off) {
+; CHECK-LABEL: @gep_sdiv_nuw(
+; CHECK-NEXT:    [[PTR:%.*]] = getelementptr nuw i8, ptr [[P:%.*]], i64 [[OFF:%.*]]
+; CHECK-NEXT:    ret ptr [[PTR]]
+;
+  %index = sdiv exact i64 %off, 7
+  %ptr = getelementptr nuw %struct.C, ptr %p, i64 %index
+  ret ptr %ptr
+}
+
 define ptr @gep_ashr(ptr %p, i64 %off) {
 ; CHECK-LABEL: @gep_ashr(
 ; CHECK-NEXT:    [[PTR:%.*]] = getelementptr i8, ptr [[P:%.*]], i64 [[OFF:%.*]]