InstSimplify: Don't simplify gep X, (Y-X) to Y if types differ
It's incorrect to perform this simplification if the types differ.
A bitcast would need to be inserted for this to work.
This fixes PR20771.
llvm-svn: 216597
diff --git a/llvm/test/Transforms/InstSimplify/gep.ll b/llvm/test/Transforms/InstSimplify/gep.ll
index d1704bf..49a97f1 100644
--- a/llvm/test/Transforms/InstSimplify/gep.ll
+++ b/llvm/test/Transforms/InstSimplify/gep.ll
@@ -64,3 +64,17 @@
; CHECK-LABEL: @test6
; CHECK-NEXT: ret i64* null
}
+
+define i8* @test7(i8* %b, i8** %e) {
+ %e_ptr = ptrtoint i8** %e to i64
+ %b_ptr = ptrtoint i8* %b to i64
+ %sub = sub i64 %e_ptr, %b_ptr
+ %gep = getelementptr inbounds i8* %b, i64 %sub
+ ret i8* %gep
+; CHECK-LABEL: @test7
+; CHECK-NEXT: ptrtoint
+; CHECK-NEXT: ptrtoint
+; CHECK-NEXT: sub
+; CHECK-NEXT: getelementptr
+; CHECK-NEXT: ret
+}