[llvm-commits] [llvm] r52525 - in /llvm/trunk: lib/Transforms/Scalar/InstructionCombining.cpp test/Transforms/InstCombine/2008-06-19-UncondLoad.ll

[Chris Lattner]

Author: lattner
Date: Fri Jun 20 00:12:56 2008
New Revision: 52525

URL: http://llvm.org/viewvc/llvm-project?rev=52525&view=rev
Log:
Fix PR2471, which is a bug involving an invalid promotion from a conditional load.

Added:
    llvm/trunk/test/Transforms/InstCombine/2008-06-19-UncondLoad.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=52525&r1=52524&r2=52525&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Fri Jun 20 00:12:56 2008
@@ -10062,10 +10062,16 @@
   while (BBI != E) {
     --BBI;
 
+    // If we see a free or a call (which might do a free) the pointer could be
+    // marked invalid.
+    if (isa<FreeInst>(BBI) || isa<CallInst>(BBI))
+      return false;
+    
     if (LoadInst *LI = dyn_cast<LoadInst>(BBI)) {
       if (LI->getOperand(0) == V) return true;
-    } else if (StoreInst *SI = dyn_cast<StoreInst>(BBI))
+    } else if (StoreInst *SI = dyn_cast<StoreInst>(BBI)) {
       if (SI->getOperand(1) == V) return true;
+    }
 
   }
   return false;

Added: llvm/trunk/test/Transforms/InstCombine/2008-06-19-UncondLoad.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/2008-06-19-UncondLoad.ll?rev=52525&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/2008-06-19-UncondLoad.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/2008-06-19-UncondLoad.ll Fri Jun 20 00:12:56 2008
@@ -0,0 +1,16 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep load | count 3
+; PR2471
+
+declare i32 @x(i32*)
+define i32 @b(i32* %a, i32* %b) {
+entry:
+        %tmp1 = load i32* %a            
+        %tmp3 = load i32* %b           
+        %add = add i32 %tmp1, %tmp3   
+        %call = call i32 @x( i32* %a )
+        %tobool = icmp ne i32 %add, 0
+	; not safe to turn into an uncond load
+        %cond = select i1 %tobool, i32* %b, i32* %a             
+        %tmp8 = load i32* %cond       
+        ret i32 %tmp8
+}