[llvm-commits] [llvm] r151452 - in /llvm/trunk: lib/Analysis/InstructionSimplify.cpp test/Transforms/InstSimplify/compare.ll

[Nick Lewycky]

Author: nicholas
Date: Sat Feb 25 14:19:07 2012
New Revision: 151452

URL: http://llvm.org/viewvc/llvm-project?rev=151452&view=rev
Log:
An argument and a local identified object (eg. a noalias call) could turn out
equal if both are null. In the test, scope type %t and global @y by adding a
'gep' prefix to them.

Modified:
    llvm/trunk/lib/Analysis/InstructionSimplify.cpp
    llvm/trunk/test/Transforms/InstSimplify/compare.ll

Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=151452&r1=151451&r2=151452&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Sat Feb 25 14:19:07 2012
@@ -1626,21 +1626,22 @@
   LHSPtr = stripPointerAdjustments(LHSPtr);
   if (llvm::isIdentifiedObject(LHSPtr)) {
     RHSPtr = stripPointerAdjustments(RHSPtr);
-    // If both sides are different identified objects, they aren't equal unless
-    // they're null.
-    if (LHSPtr != RHSPtr && llvm::isIdentifiedObject(RHSPtr) &&
-        (llvm::isKnownNonNull(LHSPtr) || llvm::isKnownNonNull(RHSPtr)))
-      return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
+    if (llvm::isKnownNonNull(LHSPtr) || llvm::isKnownNonNull(RHSPtr)) {
+      // If both sides are different identified objects, they aren't equal
+      // unless they're null.
+      if (LHSPtr != RHSPtr && llvm::isIdentifiedObject(RHSPtr))
+        return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
+
+      // A local identified object (alloca or noalias call) can't equal any
+      // incoming argument, unless they're both null.
+      if ((isa<Instruction>(LHSPtr) && isa<Argument>(RHSPtr)) ||
+          (isa<Instruction>(RHSPtr) && isa<Argument>(LHSPtr)))
+        return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
+    }
 
-    // Assume that the null is on the right.
+    // Assume that the constant null is on the right.
     if (llvm::isKnownNonNull(LHSPtr) && isa<ConstantPointerNull>(RHSPtr))
       return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
-
-    // A local instruction (alloca or noalias call) can't equal any incoming
-    // argument.
-    if ((isa<Instruction>(LHSPtr) && isa<Argument>(RHSPtr)) ||
-        (isa<Instruction>(RHSPtr) && isa<Argument>(LHSPtr)))
-      return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
   }
 
   // If we are comparing with zero then try hard since this is a common case.

Modified: llvm/trunk/test/Transforms/InstSimplify/compare.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/compare.ll?rev=151452&r1=151451&r2=151452&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/compare.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/compare.ll Sat Feb 25 14:19:07 2012
@@ -41,14 +41,15 @@
 }
 
 ; PR11238
-%t = type { i32, i32 }
- at y = global %t zeroinitializer, align 8
+%gept = type { i32, i32 }
+ at gepy = global %gept zeroinitializer, align 8
+ at gepz = extern_weak global %gept
 
 define i1 @gep3() {
 ; CHECK: @gep3
-  %x = alloca %t, align 8
-  %a = getelementptr %t* %x, i64 0, i32 0
-  %b = getelementptr %t* %x, i64 0, i32 1
+  %x = alloca %gept, align 8
+  %a = getelementptr %gept* %x, i64 0, i32 0
+  %b = getelementptr %gept* %x, i64 0, i32 1
   %equal = icmp eq i32* %a, %b
   ret i1 %equal
 ; CHECK-NEXT: ret i1 false
@@ -56,9 +57,9 @@
 
 define i1 @gep4() {
 ; CHECK: @gep4
-  %x = alloca %t, align 8
-  %a = getelementptr %t* @y, i64 0, i32 0
-  %b = getelementptr %t* @y, i64 0, i32 1
+  %x = alloca %gept, align 8
+  %a = getelementptr %gept* @gepy, i64 0, i32 0
+  %b = getelementptr %gept* @gepy, i64 0, i32 1
   %equal = icmp eq i32* %a, %b
   ret i1 %equal
 ; CHECK-NEXT: ret i1 false
@@ -66,24 +67,33 @@
 
 define i1 @gep5() {
 ; CHECK: @gep5
-  %x = alloca %t, align 8
-  %a = getelementptr inbounds %t* %x, i64 0, i32 1
-  %b = getelementptr %t* @y, i64 0, i32 0
+  %x = alloca %gept, align 8
+  %a = getelementptr inbounds %gept* %x, i64 0, i32 1
+  %b = getelementptr %gept* @gepy, i64 0, i32 0
   %equal = icmp eq i32* %a, %b
   ret i1 %equal
 ; CHECK-NEXT: ret i1 false
 }
 
-define i1 @gep6(%t* %x) {
+define i1 @gep6(%gept* %x) {
 ; Same as @gep3 but potentially null.
 ; CHECK: @gep6
-  %a = getelementptr %t* %x, i64 0, i32 0
-  %b = getelementptr %t* %x, i64 0, i32 1
+  %a = getelementptr %gept* %x, i64 0, i32 0
+  %b = getelementptr %gept* %x, i64 0, i32 1
   %equal = icmp eq i32* %a, %b
   ret i1 %equal
 ; CHECK-NEXT: ret i1 false
 }
 
+define i1 @gep7(%gept* %x) {
+; CHECK: @gep7
+  %a = getelementptr %gept* %x, i64 0, i32 0
+  %b = getelementptr %gept* @gepz, i64 0, i32 0
+  %equal = icmp eq i32* %a, %b
+  ret i1 %equal
+; CHECK: ret i1 %equal
+}
+
 define i1 @zext(i32 %x) {
 ; CHECK: @zext
   %e1 = zext i32 %x to i64