maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[MergeICmps] Handle chains with several complex BCE basic blocks. 

- Fix condition for detecting that a complex basic block was the first in
   the chain.
 - Add tests.

This was caught by buildbots when submitting rL324319.

llvm-svn: 324341
This commit is contained in:
Clement Courbet 2018-02-06 12:25:33 +00:00
parent 9dc740d0a9
commit a7a1746865
2 changed files with 62 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
llvm/lib/Transforms/Scalar/MergeICmps.cpp
View File

@ -278,7 +278,8 @@ BCECmpChain::BCECmpChain(const std::vector<BasicBlock *> &Blocks, PHINode &Phi)
assert(!Blocks.empty() && "a chain should have at least one block");
// Now look inside blocks to check for BCE comparisons.
std::vector<BCECmpBlock> Comparisons;
for (BasicBlock *Block : Blocks) {
for (size_t BlockIdx = 0; BlockIdx < Blocks.size(); ++BlockIdx) {
BasicBlock *const Block = Blocks[BlockIdx];
assert(Block && "invalid block");
BCECmpBlock Comparison = visitCmpBlock(Phi.getIncomingValueForBlock(Block),
Block, Phi.getParent());
@ -289,7 +290,7 @@ BCECmpChain::BCECmpChain(const std::vector<BasicBlock *> &Blocks, PHINode &Phi)
}
if (Comparison.doesOtherWork()) {
DEBUG(dbgs() << "block does extra work besides compare\n");
if (Comparisons.empty()) { // First block.
if (BlockIdx == 0) { // First block.
// TODO(courbet): The first block can do other things, and we should
// split them apart in a separate block before the comparison chain.
// Right now we just discard it and make the chain shorter.
@ -330,7 +331,7 @@ BCECmpChain::BCECmpChain(const std::vector<BasicBlock *> &Blocks, PHINode &Phi)
DEBUG(dbgs() << "\n");
Comparisons.push_back(Comparison);
}
assert(!Comparisons.empty() && "chain with a single complex basic block");
assert(!Comparisons.empty() && "chain with no BCE basic blocks");
EntryBlock_ = Comparisons[0].BB;
Comparisons_ = std::move(Comparisons);
#ifdef MERGEICMPS_DOT_ON

58
llvm/test/Transforms/MergeICmps/X86/two-complex-bb.ll Normal file
View File

@ -0,0 +1,58 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -mergeicmps -mtriple=x86_64-unknown-unknown -S | FileCheck %s --check-prefix=X86
%"struct.std::pair" = type { i32, i32 }
; This tests a function with two complex basic blocks.
define zeroext i1 @twocomplexblocks(
; X86-LABEL: @twocomplexblocks(
; X86-NEXT: entry:
; X86-NEXT: [[FIRST_I:%.*]] = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* [[A:%.*]], i64 0, i32 0
; X86-NEXT: [[TMP0:%.*]] = load i32, i32* [[FIRST_I]], align 4
; X86-NEXT: [[FIRST1_I:%.*]] = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* [[B:%.*]], i64 0, i32 0
; X86-NEXT: [[TMP1:%.*]] = load i32, i32* [[FIRST1_I]], align 4
; X86-NEXT: [[EXTRAWORK:%.*]] = add i32 [[TMP0]], [[TMP1]]
; X86-NEXT: [[CMP_I:%.*]] = icmp eq i32 [[TMP0]], [[TMP1]]
; X86-NEXT: br i1 [[CMP_I]], label [[LAND_RHS_I:%.*]], label [[OPEQ1_EXIT:%.*]]
; X86: land.rhs.i:
; X86-NEXT: [[SECOND_I:%.*]] = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* [[A]], i64 0, i32 1
; X86-NEXT: [[TMP2:%.*]] = load i32, i32* [[SECOND_I]], align 4
; X86-NEXT: [[SECOND2_I:%.*]] = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* [[B]], i64 0, i32 1
; X86-NEXT: [[TMP3:%.*]] = load i32, i32* [[SECOND2_I]], align 4
; X86-NEXT: [[EXTRAWORK2:%.*]] = add i32 [[TMP2]], [[TMP3]]
; X86-NEXT: [[CMP3_I:%.*]] = icmp eq i32 [[TMP2]], [[TMP3]]
; X86-NEXT: br label [[OPEQ1_EXIT]]
; X86: opeq1.exit:
; X86-NEXT: [[TMP4:%.*]] = phi i1 [ false, [[ENTRY:%.*]] ], [ [[CMP3_I]], [[LAND_RHS_I]] ]
; X86-NEXT: ret i1 [[TMP4]]
;
%"struct.std::pair"* nocapture readonly dereferenceable(8) %a,
%"struct.std::pair"* nocapture readonly dereferenceable(8) %b) local_unnamed_addr #0 {
entry:
; This is a complex BCE Basic Block.
%first.i = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* %a, i64 0, i32 0
%0 = load i32, i32* %first.i, align 4
%first1.i = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* %b, i64 0, i32 0
%1 = load i32, i32* %first1.i, align 4
%extrawork = add i32 %0, %1
%cmp.i = icmp eq i32 %0, %1
br i1 %cmp.i, label %land.rhs.i, label %opeq1.exit
land.rhs.i:
; This is a complex BCE Basic Block.
%second.i = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* %a, i64 0, i32 1
%2 = load i32, i32* %second.i, align 4
%second2.i = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* %b, i64 0, i32 1
%3 = load i32, i32* %second2.i, align 4
%extrawork2 = add i32 %2, %3
%cmp3.i = icmp eq i32 %2, %3
br label %opeq1.exit
opeq1.exit:
%4 = phi i1 [ false, %entry ], [ %cmp3.i, %land.rhs.i ]
ret i1 %4
}