This is an archive of the discontinued LLVM Phabricator instance.

Differential D38334

Enable critical edge split for indirectbr instruction
AbandonedPublic

Authored by xur on Sep 27 2017, 2:14 PM.

Details

Reviewers
davidxl
Summary

This is exposed in PGO instrumentation. I believe this is an over assert -- current logic can handle the split for the indirectbr instruction.

This patch removes the assert.

Diff Detail

Event Timeline

xur created this revision.Sep 27 2017, 2:14 PM
xur abandoned this revision.Sep 27 2017, 2:23 PM

This patch is wrong. Please ignore.

Revision Contents

PathSize
lib/
Transforms/
Utils/
3 lines
test/
Transforms/
PGOProfile/
47 lines

Diff 116879

lib/Transforms/Utils/BreakCriticalEdges.cpp

Show First 20 Lines • Show All 125 Lines • ▼ Show 20 Lines
} }
BasicBlock * BasicBlock *
llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum,
const CriticalEdgeSplittingOptions &Options) { const CriticalEdgeSplittingOptions &Options) {
if (!isCriticalEdge(TI, SuccNum, Options.MergeIdenticalEdges)) if (!isCriticalEdge(TI, SuccNum, Options.MergeIdenticalEdges))
return nullptr; return nullptr;
assert(!isa<IndirectBrInst>(TI) &&
"Cannot split critical edge from IndirectBrInst");
BasicBlock *TIBB = TI->getParent(); BasicBlock *TIBB = TI->getParent();
BasicBlock *DestBB = TI->getSuccessor(SuccNum); BasicBlock *DestBB = TI->getSuccessor(SuccNum);
// Splitting the critical edge to a pad block is non-trivial. Don't do // Splitting the critical edge to a pad block is non-trivial. Don't do
// it in this generic function. // it in this generic function.
if (DestBB->isEHPad()) return nullptr; if (DestBB->isEHPad()) return nullptr;
// Create a new basic block, linking it into the CFG. // Create a new basic block, linking it into the CFG.
▲ Show 20 Lines • Show All 148 Lines • Show Last 20 Lines

test/Transforms/PGOProfile/indirectbr_criticaledge.ll

; RUN: opt < %s -pgo-instr-gen -S | FileCheck %s
; RUN: opt < %s -passes=pgo-instr-gen -S | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define i32 @foo(i8* nocapture readonly %p) {
entry:
%targets = alloca [256 x i8*], align 16
br label %for.body
for.body:
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%arrayidx = getelementptr inbounds [256 x i8*], [256 x i8*]* %targets, i64 0, i64 %indvars.iv
store i8* blockaddress(@foo, %for.cond2), i8** %arrayidx, align 8
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%exitcond = icmp eq i64 %indvars.iv.next, 256
br i1 %exitcond, label %for.end, label %for.body
for.end:
%arrayidx1 = getelementptr inbounds [256 x i8*], [256 x i8*]* %targets, i64 0, i64 93
store i8* blockaddress(@foo, %if.end), i8** %arrayidx1, align 8
br label %for.cond2
for.cond2:
%p.addr.0 = phi i8* [ %p, %for.end ], [ %incdec.ptr5, %if.end ], [ %incdec.ptr, %for.cond2 ]
%incdec.ptr = getelementptr inbounds i8, i8* %p.addr.0, i64 1
%0 = load i8, i8* %p.addr.0, align 1
%cond = icmp eq i8 %0, 93
br i1 %cond, label %if.end.preheader, label %for.cond2
if.end.preheader:
br label %if.end
if.end:
%p.addr.1 = phi i8* [ %incdec.ptr5, %if.end ], [ %incdec.ptr, %if.end.preheader ]
%incdec.ptr5 = getelementptr inbounds i8, i8* %p.addr.1, i64 1
%1 = load i8, i8* %p.addr.1, align 1
%idxprom6 = zext i8 %1 to i64
%arrayidx7 = getelementptr inbounds [256 x i8*], [256 x i8*]* %targets, i64 0, i64 %idxprom6
%2 = load i8*, i8** %arrayidx7, align 8
indirectbr i8* %2, [label %for.cond2, label %if.end]
; CHECK indirectbr i8* %2, [label %for.cond2, label %if.end.if.end_crit_edge]
; CHECK: if.end.if.end_crit_edge:
; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @__profn_foo, i32 0, i32 0), i64 44930229957, i32 4, i32 0)
; CHECK: br label %if.end
}