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[GVNHoist] Move GVNHoist to function simplification part of pipeline. 

Summary:
Move GVNHoist to later in the optimization pipeline, specifically, to
the function simplification part of the pipeline.  The new pipeline
location allows GVNHoist to run on a function after its callees have
been inlined but before the function has been considered for inlining
into its callers, exposing more opportunities for hoisting.

Performance results on AArch64 kryo:
Improvements:
  Benchmarks/CoyoteBench/fftbench  -24.952%
  spec2006/bzip2                    -4.071%
  internal bmark                    -3.177%
  Benchmarks/PAQ8p/paq8p            -1.754%
  spec2000/perlbmk                  -1.328%
  spec2006/h264ref                  -1.140%

Regressions:
  internal bmark                    +1.818%
  Benchmarks/mafft/pairlocalalign   +1.084%

Reviewers: sebpop, dberlin, hiraditya

Subscribers: aemerson, mehdi_amini, mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D27722

llvm-svn: 289696
This commit is contained in:
Geoff Berry 2016-12-14 19:38:22 +00:00
parent 09558cb8a4
commit ca11a1e147
2 changed files with 40 additions and 2 deletions
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4
llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
View File

@ -249,8 +249,6 @@ void PassManagerBuilder::populateFunctionPassManager(
FPM.add(createCFGSimplificationPass());
FPM.add(createSROAPass());
FPM.add(createEarlyCSEPass());
if(EnableGVNHoist)
FPM.add(createGVNHoistPass());
FPM.add(createLowerExpectIntrinsicPass());
}
@ -295,6 +293,8 @@ void PassManagerBuilder::addFunctionSimplificationPasses(
// Break up aggregate allocas, using SSAUpdater.
MPM.add(createSROAPass());
MPM.add(createEarlyCSEPass()); // Catch trivial redundancies
if(EnableGVNHoist)
MPM.add(createGVNHoistPass());
// Speculative execution if the target has divergent branches; otherwise nop.
MPM.add(createSpeculativeExecutionIfHasBranchDivergencePass());
MPM.add(createJumpThreadingPass()); // Thread jumps.

38
llvm/test/Transforms/GVNHoist/hoist-inline.ll Normal file
View File

@ -0,0 +1,38 @@
; RUN: opt -S -O2 < %s | FileCheck %s
; Check that the inlined loads are hoisted.
; CHECK-LABEL: define i32 @fun(
; CHECK-LABEL: entry:
; CHECK: load i32, i32* @A
; CHECK: if.then:
@A = external global i32
@B = external global i32
@C = external global i32
define i32 @loadA() {
%a = load i32, i32* @A
ret i32 %a
}
define i32 @fun(i1 %c) {
entry:
br i1 %c, label %if.then, label %if.else
if.then:
store i32 1, i32* @B
%call1 = call i32 @loadA()
store i32 2, i32* @C
br label %if.endif
if.else:
store i32 2, i32* @C
%call2 = call i32 @loadA()
store i32 1, i32* @B
br label %if.endif
if.endif:
%ret = phi i32 [ %call1, %if.then ], [ %call2, %if.else ]
ret i32 %ret
}