Reapply Move "auto-init" instructions to the dominator of their users

Original patch (50b2a113db197a97f60ad2aace8b7382dc9b8c31) ignored the
fact that -ftrivial-auto-var-init could affect function parameters with
the sret attribute.
Just do not move instruction that don't affect alloca.
Also add missing test case for volatile instruction.

Differential Revision: https://reviews.llvm.org/D148507

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/Passes/PassBuilderPipelines.cpp b/llvm/lib/Passes/PassBuilderPipelines.cpp
index 4407ad0..2b392f1 100644
--- a/llvm/lib/Passes/PassBuilderPipelines.cpp
+++ b/llvm/lib/Passes/PassBuilderPipelines.cpp
@@ -124,6 +124,7 @@
 #include "llvm/Transforms/Utils/InjectTLIMappings.h"
 #include "llvm/Transforms/Utils/LibCallsShrinkWrap.h"
 #include "llvm/Transforms/Utils/Mem2Reg.h"
+#include "llvm/Transforms/Utils/MoveAutoInit.h"
 #include "llvm/Transforms/Utils/NameAnonGlobals.h"
 #include "llvm/Transforms/Utils/RelLookupTableConverter.h"
 #include "llvm/Transforms/Utils/SimplifyCFGOptions.h"
@@ -696,6 +697,8 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
   FPM.addPass(MemCpyOptPass());
 
   FPM.addPass(DSEPass());
+  FPM.addPass(MoveAutoInitPass());
+
   FPM.addPass(createFunctionToLoopPassAdaptor(
       LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
                /*AllowSpeculation=*/true),
@@ -1809,6 +1812,7 @@ PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
 
   // Nuke dead stores.
   MainFPM.addPass(DSEPass());
+  MainFPM.addPass(MoveAutoInitPass());
   MainFPM.addPass(MergedLoadStoreMotionPass());
 
   LoopPassManager LPM;