llvm/test/CodeGen/ARM/ifcvt-branch-weight-bug.ll
Akira Hatanaka 268c0509a9 Fix a bug in which BranchProbabilityInfo wasn't setting branch weights of basic blocks inside loops correctly.
Previously, BranchProbabilityInfo::calcLoopBranchHeuristics would determine the weights of basic blocks inside loops even when it didn't have enough information to estimate the branch probabilities correctly. This patch fixes the function to exit early if it doesn't see any exit edges or back edges and let the later heuristics determine the weights.

This fixes PR18705 and <rdar://problem/15991090>.

Differential Revision: http://reviews.llvm.org/D3363



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206194 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-14 16:56:19 +00:00

64 lines
1.9 KiB
LLVM

; RUN: llc < %s -mtriple=armv4t--linux-androideabi -print-machineinstrs=if-converter -o /dev/null 2>&1 | FileCheck %s
; Fix a bug triggered in IfConverterTriangle when CvtBB has multiple
; predecessors.
; PR18752
%classK = type { i8, %classF }
%classF = type { i8 }
%classL = type { %classG, i32, i32 }
%classG = type { %classL* }
%classM2 = type { %classL }
define zeroext i1 @test(%classK* %this, %classM2* nocapture readnone %p1, %classM2* nocapture readnone %p2) align 2 {
entry:
br i1 undef, label %for.end, label %for.body
; Before if conversion, we have
; for.body -> lor.lhs.false.i (62)
; -> for.cond.backedge (62)
; lor.lhs.false.i -> for.cond.backedge (1048575)
; -> cond.false.i (1)
; Afer if conversion, we have
; for.body -> for.cond.backedge (130023362)
; -> cond.false.i (62)
; CHECK: BB#1: derived from LLVM BB %for.body
; CHECK: Successors according to CFG: BB#2(130023362) BB#4(62)
for.body:
br i1 undef, label %for.cond.backedge, label %lor.lhs.false.i, !prof !1
for.cond.backedge:
%tobool = icmp eq %classL* undef, null
br i1 %tobool, label %for.end, label %for.body
lor.lhs.false.i:
%tobool.i.i7 = icmp eq i32 undef, 0
br i1 %tobool.i.i7, label %for.cond.backedge, label %cond.false.i
cond.false.i:
call void @_Z3fn1v()
unreachable
for.end:
br i1 undef, label %if.else.i.i, label %if.then.i.i
if.then.i.i:
store %classL* null, %classL** undef, align 4
br label %_ZN1M6spliceEv.exit
if.else.i.i:
store %classL* null, %classL** null, align 4
br label %_ZN1M6spliceEv.exit
_ZN1M6spliceEv.exit:
%LIS = getelementptr inbounds %classK* %this, i32 0, i32 1
call void @_ZN1F10handleMoveEb(%classF* %LIS, i1 zeroext false)
unreachable
}
declare %classL* @_ZN1M1JI1LS1_EcvPS1_Ev(%classM2*)
declare void @_ZN1F10handleMoveEb(%classF*, i1 zeroext)
declare void @_Z3fn1v()
!0 = metadata !{metadata !"clang version 3.5"}
!1 = metadata !{metadata !"branch_weights", i32 62, i32 62}