[PATCH] D18528: Don't fold double constant to an integer if dest type not integral

[Teresa Johnson via llvm-commits]

tejohnson created this revision.
tejohnson added a subscriber: llvm-commits.

I encountered this issue when constant folding during inlining tried to
fold away a bitcast of a double to an x86_mmx, which is not an integral
type. The test case exposes the same issue with a smaller code snippet
during early CSE.

http://reviews.llvm.org/D18528

Files:
  lib/IR/ConstantFold.cpp
  test/CodeGen/X86/mmx-bitcast-fold.ll

Index: test/CodeGen/X86/mmx-bitcast-fold.ll
===================================================================
--- /dev/null
+++ test/CodeGen/X86/mmx-bitcast-fold.ll
@@ -0,0 +1,12 @@
+; RUN: opt -mtriple=x86_64-linux-gnu -early-cse < %s -S | FileCheck %s
+
+; CHECK: @foo(x86_mmx bitcast (double 0.000000e+00 to x86_mmx))
+
+define internal void @bar() {
+entry:
+  %0 = bitcast double 0.0 to x86_mmx
+  %1 = tail call x86_mmx @foo(x86_mmx %0)
+  ret void
+}
+
+declare x86_mmx @foo(x86_mmx)
Index: lib/IR/ConstantFold.cpp
===================================================================
--- lib/IR/ConstantFold.cpp
+++ lib/IR/ConstantFold.cpp
@@ -191,6 +191,10 @@
     if (FP->getType()->isPPC_FP128Ty())
       return nullptr;
 
+    // Make sure dest type is compatible with the folded integer constant.
+    if (!DestTy->isIntegerTy())
+      return nullptr;
+
     return ConstantInt::get(FP->getContext(),
                             FP->getValueAPF().bitcastToAPInt());
   }


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