[PATCH] D95088: [InstCombine] avoid crashing on attribute propagation

[Sanjay Patel via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
spatel marked an inline comment as done.
Closed by commit rG070af1b7887f: [InstCombine] avoid crashing on attribute propagation (authored by spatel).

Changed prior to commit:
  https://reviews.llvm.org/D95088?vs=317993&id=318166#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D95088/new/

https://reviews.llvm.org/D95088

Files:
  llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
  llvm/test/Transforms/InstCombine/mempcpy.ll


Index: llvm/test/Transforms/InstCombine/mempcpy.ll
===================================================================
--- llvm/test/Transforms/InstCombine/mempcpy.ll
+++ llvm/test/Transforms/InstCombine/mempcpy.ll
@@ -53,4 +53,15 @@
   ret i8* %r
 }
 
+; The original call may have attributes that can not propagate to memcpy.
+
+define i32 @PR48810() {
+; CHECK-LABEL: @PR48810(
+; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 1 undef, i8* align 536870912 null, i64 undef, i1 false)
+; CHECK-NEXT:    ret i32 undef
+;
+  %r = call dereferenceable(1) i8* @mempcpy(i8* undef, i8* null, i64 undef)
+  ret i32 undef
+}
+
 declare i8* @mempcpy(i8*, i8* nocapture readonly, i64)
Index: llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
===================================================================
--- llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -1150,7 +1150,12 @@
   // mempcpy(x, y, n) -> llvm.memcpy(align 1 x, align 1 y, n), x + n
   CallInst *NewCI =
       B.CreateMemCpy(Dst, Align(1), CI->getArgOperand(1), Align(1), N);
+  // Propagate attributes, but memcpy has no return value, so make sure that
+  // any return attributes are compliant.
+  // TODO: Attach return value attributes to the 1st operand to preserve them?
   NewCI->setAttributes(CI->getAttributes());
+  NewCI->removeAttributes(AttributeList::ReturnIndex,
+                          AttributeFuncs::typeIncompatible(NewCI->getType()));
   return B.CreateInBoundsGEP(B.getInt8Ty(), Dst, N);
 }
 


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