[llvm] aea042e - [NFC][InstSimplify] Add a note to PHI CSE tests that they are all negative tests

[Roman Lebedev via llvm-commits]

Author: Roman Lebedev
Date: 2020-08-29T13:13:06+03:00
New Revision: aea042e978bf7b7af95336916750b4f737044291

URL: https://github.com/llvm/llvm-project/commit/aea042e978bf7b7af95336916750b4f737044291
DIFF: https://github.com/llvm/llvm-project/commit/aea042e978bf7b7af95336916750b4f737044291.diff

LOG: [NFC][InstSimplify] Add a note to PHI CSE tests that they are all negative tests

As discussed in https://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20200824/824235.html
even though it seems worthwhile doing so in InstSimplify,
we really can't do that there, because the other PHI wouldn't be
def-reachable from the original PHI.

Added: 
    

Modified: 
    llvm/test/Transforms/InstSimplify/phi-cse.ll

Removed: 
    


################################################################################
diff  --git a/llvm/test/Transforms/InstSimplify/phi-cse.ll b/llvm/test/Transforms/InstSimplify/phi-cse.ll
index a032adff0526..91bf01e0acbd 100644
--- a/llvm/test/Transforms/InstSimplify/phi-cse.ll
+++ b/llvm/test/Transforms/InstSimplify/phi-cse.ll
@@ -1,6 +1,10 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -instsimplify -S < %s | FileCheck %s
 
+; All these are negative cases, we are not allowed to perform this
+; simplification in InstSimplify, because the PHI's aren't def-reachable
+; from one another.
+
 ; Most basic case, fully identical PHI nodes
 define void @test0(i32 %v0, i32 %v1, i1 %c, i32* %d0, i32* %d1) {
 ; CHECK-LABEL: @test0(