[llvm-commits] [llvm] r52257 - in /llvm/trunk: lib/Transforms/Scalar/InstructionCombining.cpp test/Transforms/InstCombine/2008-06-13-InfiniteLoopStore.ll

[Eli Friedman]

Author: efriedma
Date: Fri Jun 13 16:17:49 2008
New Revision: 52257

URL: http://llvm.org/viewvc/llvm-project?rev=52257&view=rev
Log:
Make sure SimplifyStoreAtEndOfBlock doesn't mess with loops; the 
structure checks are incorrect if the blocks aren't distinct.
Fixes PR2435.


Added:
    llvm/trunk/test/Transforms/InstCombine/2008-06-13-InfiniteLoopStore.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=52257&r1=52256&r2=52257&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Fri Jun 13 16:17:49 2008
@@ -10379,8 +10379,12 @@
   }
   if (++PI != pred_end(DestBB))
     return false;
-  
-  
+
+  // Bail out if all the relevant blocks aren't distinct (this can happen,
+  // for example, if SI is in an infinite loop)
+  if (StoreBB == DestBB || OtherBB == DestBB)
+    return false;
+
   // Verify that the other block ends in a branch and is not otherwise empty.
   BasicBlock::iterator BBI = OtherBB->getTerminator();
   BranchInst *OtherBr = dyn_cast<BranchInst>(BBI);

Added: llvm/trunk/test/Transforms/InstCombine/2008-06-13-InfiniteLoopStore.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/2008-06-13-InfiniteLoopStore.ll?rev=52257&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/2008-06-13-InfiniteLoopStore.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/2008-06-13-InfiniteLoopStore.ll Fri Jun 13 16:17:49 2008
@@ -0,0 +1,22 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {store i32} | count 2
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+target triple = "i386-apple-darwin8"
+
+ at g_139 = global i32 0           ; <i32*> [#uses=2]
+
+define void @func_56(i32 %p_60) nounwind  {
+entry:
+        store i32 1, i32* @g_139, align 4
+        %tmp1 = icmp ne i32 %p_60, 0            ; <i1> [#uses=1]
+        %tmp12 = zext i1 %tmp1 to i8            ; <i8> [#uses=1]
+        %toBool = icmp ne i8 %tmp12, 0          ; <i1> [#uses=1]
+        br i1 %toBool, label %bb, label %return
+
+bb:             ; preds = %bb, %entry
+        store i32 1, i32* @g_139, align 4
+        br label %bb
+
+return:         ; preds = %entry
+        ret void
+}
+