From 13853cf73035757fa36a410227de9c39c0e9eb26 Mon Sep 17 00:00:00 2001 From: Sanjay Patel Date: Fri, 22 Jul 2022 16:09:29 -0400 Subject: [PATCH] [PhaseOrdering] add explanatory comment for test; NFC This note was going to be added in D129650, but we solved the problem by reverting another patch, and I missed transferring the comment. --- llvm/test/Transforms/PhaseOrdering/SystemZ/sub-xor.ll | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/llvm/test/Transforms/PhaseOrdering/SystemZ/sub-xor.ll b/llvm/test/Transforms/PhaseOrdering/SystemZ/sub-xor.ll index 66870d1..23e45bc 100644 --- a/llvm/test/Transforms/PhaseOrdering/SystemZ/sub-xor.ll +++ b/llvm/test/Transforms/PhaseOrdering/SystemZ/sub-xor.ll @@ -6,6 +6,11 @@ target triple = "systemz" @ARR = internal global [100 x i32] zeroinitializer, align 4 +; This test uses 'sub' instructions for gep offsets to allow +; codegen (LSR) to create optimal asm. If 'sub' is canonicalized +; to 'xor', then the backend needs to be able to see through +; that transform to produce optimal asm. + define dso_local zeroext i32 @foo(ptr noundef %a) #0 { ; CHECK-LABEL: @foo( ; CHECK-NEXT: entry: -- 2.7.4