Recommit r317351 : Add CallSiteSplitting pass

This recommit r317351 after fixing a buildbot failure.

Original commit message:

    Summary:
    This change add a pass which tries to split a call-site to pass
    more constrained arguments if its argument is predicated in the control flow
    so that we can expose better context to the later passes (e.g, inliner, jump
    threading, or IPA-CP based function cloning, etc.).
    As of now we support two cases :

    1) If a call site is dominated by an OR condition and if any of its arguments
    are predicated on this OR condition, try to split the condition with more
    constrained arguments. For example, in the code below, we try to split the
    call site since we can predicate the argument (ptr) based on the OR condition.

    Split from :
          if (!ptr || c)
            callee(ptr);
    to :
          if (!ptr)
            callee(null ptr)  // set the known constant value
          else if (c)
            callee(nonnull ptr)  // set non-null attribute in the argument

    2) We can also split a call-site based on constant incoming values of a PHI
    For example,
    from :
          BB0:
           %c = icmp eq i32 %i1, %i2
           br i1 %c, label %BB2, label %BB1
          BB1:
           br label %BB2
          BB2:
           %p = phi i32 [ 0, %BB0 ], [ 1, %BB1 ]
           call void @bar(i32 %p)
    to
          BB0:
           %c = icmp eq i32 %i1, %i2
           br i1 %c, label %BB2-split0, label %BB1
          BB1:
           br label %BB2-split1
          BB2-split0:
           call void @bar(i32 0)
           br label %BB2
          BB2-split1:
           call void @bar(i32 1)
           br label %BB2
          BB2:
           %p = phi i32 [ 0, %BB2-split0 ], [ 1, %BB2-split1 ]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317362 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 9 insertions, 2 deletions

diff --git a/test/Other/new-pm-defaults.ll b/test/Other/new-pm-defaults.ll
index 816f75310e3..0810a13c141 100644
--- a/test/Other/new-pm-defaults.ll
+++ b/test/Other/new-pm-defaults.ll
@@ -76,6 +76,7 @@
 ; CHECK-O-NEXT: Running pass: EarlyCSEPass
 ; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-O-NEXT: Running pass: LowerExpectIntrinsicPass
+; CHECK-O3-NEXT: Running pass: CallSiteSplittingPass
 ; CHECK-O-NEXT: Finished llvm::Function pass manager run.
 ; CHECK-O-NEXT: Running pass: IPSCCPPass
 ; CHECK-O-NEXT: Running pass: CalledValuePropagationPass
diff --git a/test/Other/new-pm-lto-defaults.ll b/test/Other/new-pm-lto-defaults.ll
index fc52f70ff4c..878198d1447 100644
--- a/test/Other/new-pm-lto-defaults.ll
+++ b/test/Other/new-pm-lto-defaults.ll
@@ -29,9 +29,14 @@
 ; CHECK-O-NEXT: Running pass: ForceFunctionAttrsPass
 ; CHECK-O-NEXT: Running pass: InferFunctionAttrsPass
 ; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
+; CHECK-O2-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}PassManager{{.*}}>
+; CHECK-O2-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*}}Module
+; CHECK-O2-NEXT: Starting llvm::Function pass manager run.
+; CHECK-O2-NEXT: Running pass: CallSiteSplittingPass on foo
+; CHECK-O2-NEXT: Running analysis: TargetLibraryAnalysis on foo
+; CHECK-O2-NEXT: Finished llvm::Function pass manager run.
 ; CHECK-O2-NEXT: PGOIndirectCallPromotion
 ; CHECK-O2-NEXT: Running analysis: ProfileSummaryAnalysis
-; CHECK-O2-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*}}Function
 ; CHECK-O2-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
 ; CHECK-O2-NEXT: Running pass: IPSCCPPass
 ; CHECK-O2-NEXT: Running pass: CalledValuePropagationPass
@@ -42,7 +47,7 @@
 ; CHECK-O-NEXT: Running analysis: FunctionAnalysisManagerCGSCCProxy
 ; CHECK-O-NEXT: Running analysis: OuterAnalysisManagerProxy<{{.*}}LazyCallGraph{{.*}}>
 ; CHECK-O-NEXT: Running analysis: AAManager
-; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
+; CHECK-O1-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-O-NEXT: Running pass: ReversePostOrderFunctionAttrsPass
 ; CHECK-O-NEXT: Running analysis: CallGraphAnalysis
 ; CHECK-O-NEXT: Running pass: GlobalSplitPass
diff --git a/test/Other/new-pm-thinlto-defaults.ll b/test/Other/new-pm-thinlto-defaults.ll
index 7d40ef3eea2..e83f0f87055 100644
--- a/test/Other/new-pm-thinlto-defaults.ll
+++ b/test/Other/new-pm-thinlto-defaults.ll
@@ -72,6 +72,7 @@
 ; CHECK-O-NEXT: Running pass: EarlyCSEPass
 ; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-O-NEXT: Running pass: LowerExpectIntrinsicPass
+; CHECK-O3-NEXT: Running pass: CallSiteSplittingPass
 ; CHECK-O-NEXT: Finished llvm::Function pass manager run.
 ; CHECK-O-NEXT: Running pass: IPSCCPPass
 ; CHECK-O-NEXT: Running pass: CalledValuePropagationPass