From: Chris Lattner <sabre@nondot.org>
Date: Thu, 2 May 2002 17:37:34 +0000 (+0000)
Subject: Fix bug: test/Regression/Transforms/LevelRaise/2002-05-02-BadCastElimination.ll
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=bbad858b3aaf905492633101f58c67d63f162dd9;p=oota-llvm.git

Fix bug: test/Regression/Transforms/LevelRaise/2002-05-02-BadCastElimination.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2429 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/ExprTypeConvert.cpp b/lib/Transforms/ExprTypeConvert.cpp
index 02ee7b2d953..7e9c9aff2b6 100644
--- a/lib/Transforms/ExprTypeConvert.cpp
+++ b/lib/Transforms/ExprTypeConvert.cpp
@@ -616,6 +616,15 @@ static bool OperandConvertableToType(User *U, Value *V, const Type *Ty,
         I->getType() == I->getOperand(0)->getType())
       return false;
 
+    // Do not allow a 'cast ushort %V to uint' to have it's first operand be
+    // converted to a 'short' type.  Doing so changes the way sign promotion
+    // happens, and breaks things.  Only allow the cast to take place if the
+    // signedness doesn't change... or if the current cast is not a lossy
+    // conversion.
+    //
+    if (!I->getType()->isLosslesslyConvertableTo(I->getOperand(0)->getType()) &&
+        I->getOperand(0)->getType()->isSigned() != Ty->isSigned())
+      return false;
 
 #if 1
     // We also do not allow conversion of a cast that casts from a ptr to array