[MemCpyOpt] Add test scaffolding for MSSA based MemCpyOpt
This adds an -enable-memcpyopt-memoryssa option that currently does
nothing apart from requiring MSSA as a dependency. The tests are
split to run both with the option disabled and enabled. I went with
this rather than the separate directory DSE uses, as I found it
convenient to have a direct side-by-side comparison of differences.
Differential Revision: https://reviews.llvm.org/D89206
diff --git a/llvm/test/Transforms/MemCpyOpt/align.ll b/llvm/test/Transforms/MemCpyOpt/align.ll
index cdaf44f..f2c7bca 100644
--- a/llvm/test/Transforms/MemCpyOpt/align.ll
+++ b/llvm/test/Transforms/MemCpyOpt/align.ll
@@ -1,5 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -S -basic-aa -memcpyopt | FileCheck %s
+; RUN: opt < %s -S -basic-aa -memcpyopt -enable-memcpyopt-memoryssa=0 | FileCheck %s --check-prefixes=CHECK,NO_MSSA
+; RUN: opt < %s -S -basic-aa -memcpyopt -enable-memcpyopt-memoryssa=1 -verify-memoryssa | FileCheck %s --check-prefixes=CHECK,MSSA
target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64"
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i1) nounwind