[llvm-commits] [llvm] r42075 - in /llvm/trunk: lib/Transforms/Scalar/LICM.cpp test/Transforms/LICM/2007-09-17-PrompteValue.ll

[Devang Patel]

Author: dpatel
Date: Mon Sep 17 20:54:42 2007
New Revision: 42075

URL: http://llvm.org/viewvc/llvm-project?rev=42075&view=rev
Log:
Fix PR1657

Added:
    llvm/trunk/test/Transforms/LICM/2007-09-17-PrompteValue.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/LICM.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/LICM.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LICM.cpp?rev=42075&r1=42074&r2=42075&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LICM.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LICM.cpp Mon Sep 17 20:54:42 2007
@@ -791,6 +791,14 @@
           break;
         }
 
+      // If GEP base is NULL then the calculated address  used by Store or
+      // Load instruction is invalid. Do not promote this value because
+      // it may expose load and store instruction that are covered by
+      // condition which may not yet folded.
+      if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(V))
+        if (isa<ConstantPointerNull>(GEP->getOperand(0)))
+          PointerOk = false;
+
       if (PointerOk) {
         const Type *Ty = cast<PointerType>(V->getType())->getElementType();
         AllocaInst *AI = new AllocaInst(Ty, 0, V->getName()+".tmp", FnStart);

Added: llvm/trunk/test/Transforms/LICM/2007-09-17-PrompteValue.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LICM/2007-09-17-PrompteValue.ll?rev=42075&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/LICM/2007-09-17-PrompteValue.ll (added)
+++ llvm/trunk/test/Transforms/LICM/2007-09-17-PrompteValue.ll Mon Sep 17 20:54:42 2007
@@ -0,0 +1,26 @@
+; ModuleID = 'PR1657.bc'
+; Do not promote getelementptr because it may exposes load from a null pointer 
+; and store from a null pointer  which are covered by 
+; icmp eq %struct.decision* null, null condition.
+; RUN: llvm-as < %s | opt -licm | llvm-dis | not grep promoted
+	%struct.decision = type { i8, %struct.decision* }
+
+define i32 @main() {
+entry:
+	br label %blah.i
+
+blah.i:		; preds = %cond_true.i, %entry
+	%tmp3.i = icmp eq %struct.decision* null, null		; <i1> [#uses=1]
+	br i1 %tmp3.i, label %clear_modes.exit, label %cond_true.i
+
+cond_true.i:		; preds = %blah.i
+	%tmp1.i = getelementptr %struct.decision* null, i32 0, i32 0		; <i8*> [#uses=1]
+	store i8 0, i8* %tmp1.i
+	br label %blah.i
+
+clear_modes.exit:		; preds = %blah.i
+	call void @exit( i32 0 )
+	unreachable
+}
+
+declare void @exit(i32)