PGO branch weight: fix PR18752.

Fix a bug triggered in IfConverterTriangle when CvtBB has multiple predecessors
by getting the weights before removing a successor.

llvm-svn: 200958

1 files changed, 62 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/ARM/ifcvt-branch-weight-bug.ll b/llvm/test/CodeGen/ARM/ifcvt-branch-weight-bug.ll
new file mode 100644
index 00000000000..86ed5b22b66
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/ifcvt-branch-weight-bug.ll
@@ -0,0 +1,62 @@
+; 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
+
+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"}