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llvm-mirror/test/Transforms/HotColdSplit/forward-dfs-reaches-marked-block.ll
Vedant Kumar 2c542e21a7 [HotColdSplitting] Outline more than once per function
Algorithm: Identify maximal cold regions and put them in a worklist. If
a candidate region overlaps with another, discard it. While the worklist
is full, remove a single-entry sub-region from the worklist and attempt
to outline it. By the non-overlap property, this should not invalidate
parts of the domtree pertaining to other outlining regions.

Testing: LNT results on X86 are clean. With test-suite + externals, llvm
outlines 134KB pre-patch, and 352KB post-patch (+ ~2.6x). The file
483.xalancbmk/src/Constants.cpp stands out as an extreme case where llvm
outlines over 100 times in some functions (mostly EH paths). There was
not a significant performance impact pre vs. post-patch.

Differential Revision: https://reviews.llvm.org/D53887

llvm-svn: 348639
2018-12-07 20:23:52 +00:00

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LLVM

; RUN: opt -hotcoldsplit -S < %s | FileCheck %s
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.14.0"
; CHECK-LABEL: define {{.*}}@fun
; CHECK: call {{.*}}@fun.cold.1(
define void @fun() {
entry:
br i1 undef, label %if.then, label %if.else
if.then:
; This will be marked by the inverse DFS on sink-predecesors.
br label %sink
sink:
call void @sink()
; Do not allow the forward-DFS on sink-successors to mark the block again.
br i1 undef, label %if.then, label %if.then.exit
if.then.exit:
ret void
if.else:
ret void
}
declare void @sink() cold