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Enhance calcColdCallHeuristics for InvokeInst

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Summary: When identifying cold blocks, consider only the edge to the normal destination if the terminator is InvokeInst and let calcInvokeHeuristics() decide edge weights for the InvokeInst.

Reviewers: mcrosier, hfinkel, davidxl

Subscribers: mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D24868

llvm-svn: 282262
This commit is contained in:
Jun Bum Lim 2016-09-23 17:26:14 +00:00
parent 1d4f73e415
commit bd9da0f624
2 changed files with 103 additions and 0 deletions
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10
lib/Analysis/BranchProbabilityInfo.cpp
View File

@ -279,6 +279,16 @@ bool BranchProbabilityInfo::calcColdCallHeuristics(const BasicBlock *BB) {
}
}
if (auto *II = dyn_cast<InvokeInst>(TI)) {
// If the terminator is an InvokeInst, consider only the normal destination
// block.
if (PostDominatedByColdCall.count(II->getNormalDest()))
PostDominatedByColdCall.insert(BB);
// Return false here so that edge weights for InvokeInst could be decided
// in calcInvokeHeuristics().
return false;
}
// Skip probabilities if this block has a single successor.
if (TI->getNumSuccessors() == 1 || ColdEdges.empty())
return false;

93
test/Analysis/BranchProbabilityInfo/basic.ll
View File

@ -176,6 +176,99 @@ exit:
ret i32 %ret
}
; CHECK-LABEL: test_invoke_code_callsite1
define i32 @test_invoke_code_callsite1(i1 %c) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
entry:
br i1 %c, label %if.then, label %if.end
; Edge "entry->if.end" should have higher probability based on the cold call
; heuristic which treat %if.then as a cold block because the normal destination
; of the invoke instruction in %if.then is post-dominated by ColdFunc().
; CHECK: edge entry -> if.then probability is 0x07878788 / 0x80000000 = 5.88%
; CHECK: edge entry -> if.end probability is 0x78787878 / 0x80000000 = 94.12% [HOT edge]
if.then:
invoke i32 @InvokeCall()
to label %invoke.cont unwind label %lpad
; CHECK: edge if.then -> invoke.cont probability is 0x7ffff800 / 0x80000000 = 100.00% [HOT edge]
; CHECK: edge if.then -> lpad probability is 0x00000800 / 0x80000000 = 0.00%
invoke.cont:
call void @ColdFunc() #0
br label %if.end
lpad:
%ll = landingpad { i8*, i32 }
cleanup
br label %if.end
if.end:
ret i32 0
}
; CHECK-LABEL: test_invoke_code_callsite2
define i32 @test_invoke_code_callsite2(i1 %c) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
entry:
br i1 %c, label %if.then, label %if.end
; CHECK: edge entry -> if.then probability is 0x40000000 / 0x80000000 = 50.00%
; CHECK: edge entry -> if.end probability is 0x40000000 / 0x80000000 = 50.00%
if.then:
invoke i32 @InvokeCall()
to label %invoke.cont unwind label %lpad
; The cold call heuristic should not kick in when the cold callsite is in EH path.
; CHECK: edge if.then -> invoke.cont probability is 0x7ffff800 / 0x80000000 = 100.00% [HOT edge]
; CHECK: edge if.then -> lpad probability is 0x00000800 / 0x80000000 = 0.00%
invoke.cont:
br label %if.end
lpad:
%ll = landingpad { i8*, i32 }
cleanup
call void @ColdFunc() #0
br label %if.end
if.end:
ret i32 0
}
; CHECK-LABEL: test_invoke_code_callsite3
define i32 @test_invoke_code_callsite3(i1 %c) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
entry:
br i1 %c, label %if.then, label %if.end
; CHECK: edge entry -> if.then probability is 0x07878788 / 0x80000000 = 5.88%
; CHECK: edge entry -> if.end probability is 0x78787878 / 0x80000000 = 94.12% [HOT edge]
if.then:
invoke i32 @InvokeCall()
to label %invoke.cont unwind label %lpad
; Regardless of cold calls, edge weights from a invoke instruction should be
; determined by the invoke heuristic.
; CHECK: edge if.then -> invoke.cont probability is 0x7ffff800 / 0x80000000 = 100.00% [HOT edge]
; CHECK: edge if.then -> lpad probability is 0x00000800 / 0x80000000 = 0.00%
invoke.cont:
call void @ColdFunc() #0
br label %if.end
lpad:
%ll = landingpad { i8*, i32 }
cleanup
call void @ColdFunc() #0
br label %if.end
if.end:
ret i32 0
}
declare i32 @__gxx_personality_v0(...)
declare void @ColdFunc()
declare i32 @InvokeCall()
attributes #0 = { cold }
define i32 @zero1(i32 %i, i32 %a, i32 %b) {
; CHECK: Printing analysis {{.*}} for function 'zero1'
entry: