[llvm] b9754e9 - [LTO] Run Argument Promotion before IPSCCP (#111163)

[via llvm-commits]

Author: Hari Limaye
Date: 2024-10-10T06:08:27-04:00
New Revision: b9754e9d285e6c056f04e00cc792c572d012ec02

URL: https://github.com/llvm/llvm-project/commit/b9754e9d285e6c056f04e00cc792c572d012ec02
DIFF: https://github.com/llvm/llvm-project/commit/b9754e9d285e6c056f04e00cc792c572d012ec02.diff

LOG: [LTO] Run Argument Promotion before IPSCCP (#111163)

Run ArgumentPromotion before IPSCCP in the LTO pipeline, to expose more
constants to be propagated. We also run PostOrderFunctionAttrs to
improve the information available to ArgumentPromotion's alias analysis,
and SROA to clean up allocas.

Added: 
    

Modified: 
    llvm/lib/Passes/PassBuilderPipelines.cpp
    llvm/test/Other/new-pm-lto-defaults.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Passes/PassBuilderPipelines.cpp b/llvm/lib/Passes/PassBuilderPipelines.cpp
index 8f151a99b11709..cdb9431c755bce 100644
--- a/llvm/lib/Passes/PassBuilderPipelines.cpp
+++ b/llvm/lib/Passes/PassBuilderPipelines.cpp
@@ -1831,6 +1831,15 @@ PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
     MPM.addPass(PGOIndirectCallPromotion(
         true /* InLTO */, PGOOpt && PGOOpt->Action == PGOOptions::SampleUse));
 
+    // Promoting by-reference arguments to by-value exposes more constants to
+    // IPSCCP.
+    MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(
+        PostOrderFunctionAttrsPass(/*SkipNonRecursive*/ true)));
+    MPM.addPass(
+        createModuleToPostOrderCGSCCPassAdaptor(ArgumentPromotionPass()));
+    MPM.addPass(
+        createModuleToFunctionPassAdaptor(SROAPass(SROAOptions::ModifyCFG)));
+
     // Propagate constants at call sites into the functions they call.  This
     // opens opportunities for globalopt (and inlining) by substituting function
     // pointers passed as arguments to direct uses of functions.

diff  --git a/llvm/test/Other/new-pm-lto-defaults.ll b/llvm/test/Other/new-pm-lto-defaults.ll
index 5543472df685b0..2dd754ecef4d7b 100644
--- a/llvm/test/Other/new-pm-lto-defaults.ll
+++ b/llvm/test/Other/new-pm-lto-defaults.ll
@@ -41,14 +41,17 @@
 ; CHECK-O23SZ-NEXT: PGOIndirectCallPromotion
 ; CHECK-O23SZ-NEXT: Running analysis: ProfileSummaryAnalysis
 ; CHECK-O23SZ-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
-; CHECK-O23SZ-NEXT: Running pass: IPSCCPPass
-; CHECK-O23SZ-NEXT: Running analysis: AssumptionAnalysis on foo
-; CHECK-O23SZ-NEXT: Running pass: CalledValuePropagationPass
 ; CHECK-O-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*}}SCC
 ; CHECK-O-NEXT: Running analysis: LazyCallGraphAnalysis
 ; CHECK-O1-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-O-NEXT: Running analysis: FunctionAnalysisManagerCGSCCProxy
 ; CHECK-O-NEXT: Running analysis: OuterAnalysisManagerProxy<{{.*}}LazyCallGraph{{.*}}>
+; CHECK-O23SZ-NEXT: Running pass: PostOrderFunctionAttrsPass
+; CHECK-O23SZ-NEXT: Running pass: ArgumentPromotionPass
+; CHECK-O23SZ-NEXT: Running pass: SROAPass
+; CHECK-O23SZ-NEXT: Running analysis: AssumptionAnalysis on foo
+; CHECK-O23SZ-NEXT: Running pass: IPSCCPPass
+; CHECK-O23SZ-NEXT: Running pass: CalledValuePropagationPass
 ; CHECK-O-NEXT: Running pass: PostOrderFunctionAttrsPass
 ; CHECK-O-NEXT: Running analysis: AAManager
 ; CHECK-O-NEXT: Running analysis: BasicAA