From 975ee54731476ff6541fc42f6a8cd706f3d33f58 Mon Sep 17 00:00:00 2001 From: Nadav Rotem Date: Fri, 29 Mar 2013 16:34:23 +0000 Subject: Fix a typo git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178346 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/MachineBlockPlacement.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib/CodeGen/MachineBlockPlacement.cpp') diff --git a/lib/CodeGen/MachineBlockPlacement.cpp b/lib/CodeGen/MachineBlockPlacement.cpp index 3b09c6b779..cd948e24a6 100644 --- a/lib/CodeGen/MachineBlockPlacement.cpp +++ b/lib/CodeGen/MachineBlockPlacement.cpp @@ -1061,7 +1061,7 @@ void MachineBlockPlacement::buildCFGChains(MachineFunction &F) { } // Align this block if the layout predecessor's edge into this block is - // cold relative to the block. When this is true, othe predecessors make up + // cold relative to the block. When this is true, other predecessors make up // all of the hot entries into the block and thus alignment is likely to be // important. BranchProbability LayoutProb = MBPI->getEdgeProbability(LayoutPred, *BI); -- cgit v1.2.3-70-g09d2 From 07706e5506fb1bf494667e9fd16795b6c0b4d0fb Mon Sep 17 00:00:00 2001 From: Nadav Rotem Date: Fri, 12 Apr 2013 00:48:32 +0000 Subject: Add a flag to align all basic blocks in the function. When debugging performance regressions we often ask ourselves if the regression that we see is due to poor isel/sched/ra or due to some micro-architetural problem. When comparing two code sequences one good way to rule out front-end bottlenecks (and other the issues) is to force code alignment. This pass adds a flag that forces the alignment of all of the basic blocks in the program. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179353 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/MachineBlockPlacement.cpp | 14 ++++++++++++++ test/CodeGen/X86/code_placement_align_all.ll | 22 ++++++++++++++++++++++ 2 files changed, 36 insertions(+) create mode 100644 test/CodeGen/X86/code_placement_align_all.ll (limited to 'lib/CodeGen/MachineBlockPlacement.cpp') diff --git a/lib/CodeGen/MachineBlockPlacement.cpp b/lib/CodeGen/MachineBlockPlacement.cpp index cd948e24a6..774df81b4d 100644 --- a/lib/CodeGen/MachineBlockPlacement.cpp +++ b/lib/CodeGen/MachineBlockPlacement.cpp @@ -39,6 +39,7 @@ #include "llvm/CodeGen/MachineLoopInfo.h" #include "llvm/CodeGen/MachineModuleInfo.h" #include "llvm/Support/Allocator.h" +#include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" #include "llvm/Target/TargetInstrInfo.h" #include "llvm/Target/TargetLowering.h" @@ -52,6 +53,11 @@ STATISTIC(CondBranchTakenFreq, STATISTIC(UncondBranchTakenFreq, "Potential frequency of taking unconditional branches"); +static cl::opt AlignAllBlock("align-all-blocks", + cl::desc("Force the alignment of all " + "blocks in the function."), + cl::init(0), cl::Hidden); + namespace { class BlockChain; /// \brief Type for our function-wide basic block -> block chain mapping. @@ -1083,6 +1089,14 @@ bool MachineBlockPlacement::runOnMachineFunction(MachineFunction &F) { TLI = F.getTarget().getTargetLowering(); assert(BlockToChain.empty()); + if (AlignAllBlock) { + // Align all of the blocks in the function to a specific alignment. + for (MachineFunction::iterator FI = F.begin(), FE = F.end(); + FI != FE; ++FI) + FI->setAlignment(AlignAllBlock); + return true; + } + buildCFGChains(F); BlockToChain.clear(); diff --git a/test/CodeGen/X86/code_placement_align_all.ll b/test/CodeGen/X86/code_placement_align_all.ll new file mode 100644 index 0000000000..2a36a3a3af --- /dev/null +++ b/test/CodeGen/X86/code_placement_align_all.ll @@ -0,0 +1,22 @@ +; RUN: llc -march=x86 -align-all-blocks=16 < %s | FileCheck %s + +;CHECK: foo +;CHECK: .align 16, 0x90 +;CHECK: .align 16, 0x90 +;CHECK: .align 16, 0x90 +;CHECK: ret +define i32 @foo(i32 %t, i32 %l) nounwind readnone ssp uwtable { + %1 = icmp eq i32 %t, 0 + br i1 %1, label %4, label %2 + +;