Teach instsimplify to be more aggressive when analyzing comparisons of pointers

by using llvm::isIdentifiedObject. Also teach it to handle GEPs that have
the same base pointer and constant operands. Fixes PR11238!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151449 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 44 insertions, 0 deletions

diff --git a/test/Transforms/InstSimplify/compare.ll b/test/Transforms/InstSimplify/compare.ll
index 6ee6dfbdbc..85aea19e69 100644
--- a/test/Transforms/InstSimplify/compare.ll
+++ b/test/Transforms/InstSimplify/compare.ll
@@ -40,6 +40,50 @@ define i1 @gep2() {
 ; CHECK-NEXT: ret i1 true
 }
 
+; PR11238
+%t = type { i32, i32 }
+@y = global %t zeroinitializer, align 8
+
+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
+  %equal = icmp eq i32* %a, %b
+  ret i1 %equal
+; CHECK-NEXT: ret i1 false
+}
+
+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
+  %equal = icmp eq i32* %a, %b
+  ret i1 %equal
+; CHECK-NEXT: ret i1 false
+}
+
+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
+  %equal = icmp eq i32* %a, %b
+  ret i1 %equal
+; CHECK-NEXT: ret i1 false
+}
+
+define i1 @gep6(%t* %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
+  %equal = icmp eq i32* %a, %b
+  ret i1 %equal
+; CHECK-NEXT: ret i1 false
+}
+
 define i1 @zext(i32 %x) {
 ; CHECK: @zext
   %e1 = zext i32 %x to i64