Don't try to create a mask when we don't need one. Fixes a crash.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58075 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp
index d3d0eb6..9f94ee3 100644 (file)
--- a/lib/Analysis/ConstantFolding.cpp
+++ b/lib/Analysis/ConstantFolding.cpp
@@ -368,10 +368,12 @@ Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy,
       if (TD && CE->getOpcode() == Instruction::IntToPtr) {
         Constant *Input = CE->getOperand(0);
         unsigned InWidth = Input->getType()->getPrimitiveSizeInBits();
-        Constant *Mask = 
-          ConstantInt::get(APInt::getLowBitsSet(InWidth,
-                                                TD->getPointerSizeInBits()));
-        Input = ConstantExpr::getAnd(Input, Mask);
+        if (TD->getPointerSizeInBits() < InWidth) {
+          Constant *Mask = 
+            ConstantInt::get(APInt::getLowBitsSet(InWidth,
+                                                  TD->getPointerSizeInBits()));
+          Input = ConstantExpr::getAnd(Input, Mask);
+        }
         // Do a zext or trunc to get to the dest size.
         return ConstantExpr::getIntegerCast(Input, DestTy, false);
       }

diff --git a/test/Transforms/InstCombine/2008-10-23-ConstFoldWithoutMask.ll b/test/Transforms/InstCombine/2008-10-23-ConstFoldWithoutMask.ll
new file mode 100644 (file)
index 0000000..8f35a85
--- /dev/null
+++ b/test/Transforms/InstCombine/2008-10-23-ConstFoldWithoutMask.ll
@@ -0,0 +1,8 @@
+; RUN: llvm-as < %s | opt -instcombine
+; PR2940
+
+define i32 @tstid() {
+       %var0 = inttoptr i32 1 to i8*           ; <i8*> [#uses=1]
+       %var2 = ptrtoint i8* %var0 to i32               ; <i32> [#uses=1]
+       ret i32 %var2
+}