[llvm] f564299 - [IROutliner] Ensure instructions at end of candidate are excluded
Andrew Litteken via llvm-commits
llvm-commits at lists.llvm.org
Mon Aug 30 09:31:10 PDT 2021
Author: Andrew Litteken
Date: 2021-08-30T09:30:26-07:00
New Revision: f564299fe94bade150c845f134284038d27b422a
URL: https://github.com/llvm/llvm-project/commit/f564299fe94bade150c845f134284038d27b422a
DIFF: https://github.com/llvm/llvm-project/commit/f564299fe94bade150c845f134284038d27b422a.diff
LOG: [IROutliner] Ensure instructions at end of candidate are excluded
Occasionally instructions are between the last instruction in a region,
and the following instruction as identified by the Candidate. This
adds an extra check right before splitting a candidate that excludes the region from being split/checked for outlining to remove errors.
Tests Added:
Tranforms/IROuutliner/outlining-extra-bitcasts.ll
Reviewer: paquette, jroelofs
Differential Revision: https://reviews.llvm.org/D104142
Added:
Modified:
llvm/lib/Transforms/IPO/IROutliner.cpp
llvm/test/Transforms/IROutliner/outlining-bitcasts.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/IPO/IROutliner.cpp b/llvm/lib/Transforms/IPO/IROutliner.cpp
index 0b5784cec350..a9841c32985a 100644
--- a/llvm/lib/Transforms/IPO/IROutliner.cpp
+++ b/llvm/lib/Transforms/IPO/IROutliner.cpp
@@ -133,9 +133,18 @@ static void moveBBContents(BasicBlock &SourceBB, BasicBlock &TargetBB) {
void OutlinableRegion::splitCandidate() {
assert(!CandidateSplit && "Candidate already split!");
- Instruction *StartInst = (*Candidate->begin()).Inst;
Instruction *EndInst = (*Candidate->end()).Inst;
- assert(StartInst && EndInst && "Expected a start and end instruction?");
+ assert(EndInst && "Expected an end instruction?");
+
+ // We check if the current instruction following the last instruction in the
+ // region is the same as the recorded instruction following the last
+ // instruction. If they do not match, there could be problems in rewriting
+ // the program after outlining, so we ignore it.
+ if (EndInst != Candidate->backInstruction()->getNextNonDebugInstruction())
+ return;
+
+ Instruction *StartInst = (*Candidate->begin()).Inst;
+ assert(StartInst && "Expected a start instruction?");
StartBB = StartInst->getParent();
PrevBB = StartBB;
@@ -1687,6 +1696,13 @@ unsigned IROutliner::doOutline(Module &M) {
// Break the outlinable region out of its parent BasicBlock into its own
// BasicBlocks (see function implementation).
OS->splitCandidate();
+
+ // There's a chance that when the region is split, extra instructions are
+ // added to the region. This makes the region no longer viable
+ // to be split, so we ignore it for outlining.
+ if (!OS->CandidateSplit)
+ continue;
+
std::vector<BasicBlock *> BE = {OS->StartBB};
OS->CE = new (ExtractorAllocator.Allocate())
CodeExtractor(BE, nullptr, false, nullptr, nullptr, nullptr, false,
diff --git a/llvm/test/Transforms/IROutliner/outlining-bitcasts.ll b/llvm/test/Transforms/IROutliner/outlining-bitcasts.ll
index 68b7eb74ec0c..f3216c2d4942 100644
--- a/llvm/test/Transforms/IROutliner/outlining-bitcasts.ll
+++ b/llvm/test/Transforms/IROutliner/outlining-bitcasts.ll
@@ -1,4 +1,4 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --include-generated-funcs
; RUN: opt -S -verify -iroutliner -ir-outlining-no-cost < %s | FileCheck %s
; This test ensures that an extra output is not added when there is a bitcast
@@ -12,15 +12,6 @@ declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture)
declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture)
define void @outline_bitcast_base() {
-; CHECK-LABEL: @outline_bitcast_base(
-; CHECK-NEXT: entry:
-; CHECK-NEXT: [[A:%.*]] = alloca i32, align 4
-; CHECK-NEXT: [[B:%.*]] = alloca i32, align 4
-; CHECK-NEXT: [[C:%.*]] = alloca i32, align 4
-; CHECK-NEXT: [[D:%.*]] = alloca i32, align 4
-; CHECK-NEXT: call void @[[FUNCTION_0:.*]](i32* [[A]], i32* [[B]], i32* [[C]], i32* [[D]])
-; CHECK-NEXT: ret void
-;
entry:
%a = alloca i32, align 4
%b = alloca i32, align 4
@@ -37,25 +28,6 @@ entry:
}
define void @outline_bitcast_removed() {
-; CHECK-LABEL: @outline_bitcast_removed(
-; CHECK-NEXT: entry:
-; CHECK-NEXT: [[A:%.*]] = alloca i32, align 4
-; CHECK-NEXT: [[B:%.*]] = alloca i32, align 4
-; CHECK-NEXT: [[C:%.*]] = alloca i32, align 4
-; CHECK-NEXT: [[D:%.*]] = alloca i32, align 4
-; CHECK-NEXT: call void @[[FUNCTION_0:.*]](i32* [[A]], i32* [[B]], i32* [[C]], i32* [[D]])
-; CHECK-NEXT: [[LT_CAST1:%.*]] = bitcast i32* [[D]] to i8*
-; CHECK-NEXT: call void @llvm.lifetime.start.p0i8(i64 -1, i8* [[LT_CAST1]])
-; CHECK-NEXT: [[AM:%.*]] = load i32, i32* [[B]], align 4
-; CHECK-NEXT: [[BM:%.*]] = load i32, i32* [[A]], align 4
-; CHECK-NEXT: [[CM:%.*]] = load i32, i32* [[C]], align 4
-; CHECK-NEXT: [[AS:%.*]] = add i32 [[AM]], [[BM]]
-; CHECK-NEXT: [[BS:%.*]] = add i32 [[BM]], [[AM]]
-; CHECK-NEXT: [[CS:%.*]] = add i32 [[BM]], [[CM]]
-; CHECK-NEXT: [[LT_CAST:%.*]] = bitcast i32* [[D]] to i8*
-; CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 -1, i8* [[LT_CAST]])
-; CHECK-NEXT: ret void
-;
entry:
%a = alloca i32, align 4
%b = alloca i32, align 4
@@ -72,34 +44,92 @@ entry:
%am = load i32, i32* %b
%bm = load i32, i32* %a
%cm = load i32, i32* %c
- %as = add i32 %am, %bm
- %bs = add i32 %bm, %am
- %cs = add i32 %bm, %cm
call void @llvm.lifetime.end.p0i8(i64 -1, i8* %X)
ret void
}
+; The first bitcast is moved down to lifetime start, and, since the original
+; endpoint does not match the new endpoint, we cannot extract and outline the
+; second bitcast and set of adds. Outlining only occurs in this case due to
+; the lack of a cost model, as denoted by the debug command line argument.
+
define void @outline_bitcast_base2(i32 %a, i32 %b, i32 %c) {
-; CHECK-LABEL: @outline_bitcast_base2(
-; CHECK-NEXT: entry:
-; CHECK-NEXT: [[AL:%.*]] = add i32 [[A:%.*]], [[B:%.*]]
-; CHECK-NEXT: [[BL:%.*]] = add i32 [[B]], [[A]]
-; CHECK-NEXT: [[CL:%.*]] = add i32 [[B]], [[C:%.*]]
-; CHECK-NEXT: ret void
-;
entry:
+ %d = alloca i32, align 4
+ %X = bitcast i32* %d to i8*
%al = add i32 %a, %b
%bl = add i32 %b, %a
%cl = add i32 %b, %c
+ %buffer = mul i32 %a, %b
+ %Y = bitcast i32* %d to i8*
+ %am = add i32 %a, %b
+ %bm = add i32 %b, %a
+ %cm = add i32 %b, %c
+ call void @llvm.lifetime.start.p0i8(i64 -1, i8* %X)
+ call void @llvm.lifetime.end.p0i8(i64 -1, i8* %X)
ret void
}
-; CHECK: define internal void @[[FUNCTION_0]](i32* [[ARG0:%.*]], i32* [[ARG1:%.*]], i32* [[ARG2:%.*]], i32* [[ARG3:%.*]])
-; CHECK: entry_to_outline:
-; CHECK-NEXT: store i32 2, i32* [[ARG0]], align 4
-; CHECK-NEXT: store i32 3, i32* [[ARG1]], align 4
-; CHECK-NEXT: store i32 4, i32* [[ARG2]], align 4
-; CHECK-NEXT: [[X:%.*]] = bitcast i32* [[ARG3]] to i8*
-; CHECK-NEXT: [[AL:%.*]] = load i32, i32* [[ARG0]], align 4
-; CHECK-NEXT: [[BL:%.*]] = load i32, i32* [[ARG1]], align 4
-; CHECK-NEXT: [[CL:%.*]] = load i32, i32* [[ARG2]], align 4
+; CHECK-LABEL: @outline_bitcast_base(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[D:%.*]] = alloca i32, align 4
+; CHECK-NEXT: call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]], i32* [[D]])
+; CHECK-NEXT: ret void
+;
+;
+; CHECK-LABEL: @outline_bitcast_removed(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[D:%.*]] = alloca i32, align 4
+; CHECK-NEXT: call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]], i32* [[D]])
+; CHECK-NEXT: [[LT_CAST1:%.*]] = bitcast i32* [[D]] to i8*
+; CHECK-NEXT: call void @llvm.lifetime.start.p0i8(i64 -1, i8* [[LT_CAST1]])
+; CHECK-NEXT: [[AM:%.*]] = load i32, i32* [[B]], align 4
+; CHECK-NEXT: [[BM:%.*]] = load i32, i32* [[A]], align 4
+; CHECK-NEXT: [[CM:%.*]] = load i32, i32* [[C]], align 4
+; CHECK-NEXT: [[LT_CAST:%.*]] = bitcast i32* [[D]] to i8*
+; CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 -1, i8* [[LT_CAST]])
+; CHECK-NEXT: ret void
+;
+;
+; CHECK-LABEL: @outline_bitcast_base2(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[D:%.*]] = alloca i32, align 4
+; CHECK-NEXT: call void @outlined_ir_func_1(i32* [[D]], i32 [[A:%.*]], i32 [[B:%.*]], i32 [[C:%.*]])
+; CHECK-NEXT: [[BUFFER:%.*]] = mul i32 [[A]], [[B]]
+; CHECK-NEXT: [[Y:%.*]] = bitcast i32* [[D]] to i8*
+; CHECK-NEXT: [[AM:%.*]] = add i32 [[A]], [[B]]
+; CHECK-NEXT: [[BM:%.*]] = add i32 [[B]], [[A]]
+; CHECK-NEXT: [[CM:%.*]] = add i32 [[B]], [[C]]
+; CHECK-NEXT: [[LT_CAST1:%.*]] = bitcast i32* [[D]] to i8*
+; CHECK-NEXT: call void @llvm.lifetime.start.p0i8(i64 -1, i8* [[LT_CAST1]])
+; CHECK-NEXT: [[LT_CAST:%.*]] = bitcast i32* [[D]] to i8*
+; CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 -1, i8* [[LT_CAST]])
+; CHECK-NEXT: ret void
+;
+;
+; CHECK: @outlined_ir_func_0(i32* [[TMP0:%.*]], i32* [[TMP1:%.*]], i32* [[TMP2:%.*]], i32* [[TMP3:%.*]])
+; CHECK: entry_to_outline:
+; CHECK-NEXT: store i32 2, i32* [[TMP0:%.*]], align 4
+; CHECK-NEXT: store i32 3, i32* [[TMP1:%.*]], align 4
+; CHECK-NEXT: store i32 4, i32* [[TMP2:%.*]], align 4
+; CHECK-NEXT: [[X:%.*]] = bitcast i32* [[TMP3:%.*]] to i8*
+; CHECK-NEXT: [[AL:%.*]] = load i32, i32* [[TMP0]], align 4
+; CHECK-NEXT: [[BL:%.*]] = load i32, i32* [[TMP1]], align 4
+; CHECK-NEXT: [[CL:%.*]] = load i32, i32* [[TMP2]], align 4
+; CHECK-NEXT: br label [[ENTRY_AFTER_OUTLINE_EXITSTUB:%.*]]
+;
+;
+; CHECK: @outlined_ir_func_1(i32* [[TMP0:%.*]], i32 [[TMP1:%.*]], i32 [[TMP2:%.*]], i32 [[TMP3:%.*]])
+; CHECK: entry_to_outline:
+; CHECK-NEXT: [[X:%.*]] = bitcast i32* [[TMP0]] to i8*
+; CHECK-NEXT: [[AL:%.*]] = add i32 [[TMP1]], [[TMP2]]
+; CHECK-NEXT: [[BL:%.*]] = add i32 [[TMP2]], [[TMP1]]
+; CHECK-NEXT: [[CL:%.*]] = add i32 [[TMP2]], [[TMP3]]
+; CHECK-NEXT: br label [[ENTRY_AFTER_OUTLINE_EXITSTUB:%.*]]
+;
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