From 8c741b8064f1116d8d8dc435b60b75abdf5c4d57 Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Tue, 6 Dec 2011 01:26:19 +0000 Subject: [PATCH] Use logarithmic units for basic block alignment. This was actually a bit of a mess. TLI.setPrefLoopAlignment was clearly documented as taking log2(bytes) units, but the x86 target would still set a preferred loop alignment of '16'. CodePlacementOpt passed this number on to the basic block, and AsmPrinter interpreted it as bytes. Now both MachineFunction and MachineBasicBlock use logarithmic alignments. Obviously, MachineConstantPool still measures alignments in bytes, so we can emulate the thrill of using as. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145889 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/CodeGen/MachineBasicBlock.h | 5 ++++- lib/CodeGen/AsmPrinter/AsmPrinter.cpp | 2 +- lib/Target/X86/X86ISelLowering.cpp | 4 ++-- 3 files changed, 7 insertions(+), 4 deletions(-) diff --git a/include/llvm/CodeGen/MachineBasicBlock.h b/include/llvm/CodeGen/MachineBasicBlock.h index 5a20e952b9c..499f62d660f 100644 --- a/include/llvm/CodeGen/MachineBasicBlock.h +++ b/include/llvm/CodeGen/MachineBasicBlock.h @@ -84,8 +84,9 @@ class MachineBasicBlock : public ilist_node { /// Alignment - Alignment of the basic block. Zero if the basic block does /// not need to be aligned. + /// The alignment is specified as log2(bytes). unsigned Alignment; - + /// IsLandingPad - Indicate that this basic block is entered via an /// exception handler. bool IsLandingPad; @@ -219,10 +220,12 @@ public: bool livein_empty() const { return LiveIns.empty(); } /// getAlignment - Return alignment of the basic block. + /// The alignment is specified as log2(bytes). /// unsigned getAlignment() const { return Alignment; } /// setAlignment - Set alignment of the basic block. + /// The alignment is specified as log2(bytes). /// void setAlignment(unsigned Align) { Alignment = Align; } diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp index d60a1f1e0a5..8c69a3aca81 100644 --- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp +++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp @@ -1970,7 +1970,7 @@ static void EmitBasicBlockLoopComments(const MachineBasicBlock &MBB, void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const { // Emit an alignment directive for this block, if needed. if (unsigned Align = MBB->getAlignment()) - EmitAlignment(Log2_32(Align)); + EmitAlignment(Align); // If the block has its address taken, emit any labels that were used to // reference the block. It is possible that there is more than one label diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp index a67d27568d0..a214c06c3b5 100644 --- a/lib/Target/X86/X86ISelLowering.cpp +++ b/lib/Target/X86/X86ISelLowering.cpp @@ -1211,10 +1211,10 @@ X86TargetLowering::X86TargetLowering(X86TargetMachine &TM) maxStoresPerMemcpyOptSize = Subtarget->isTargetDarwin() ? 8 : 4; maxStoresPerMemmove = 8; // For @llvm.memmove -> sequence of stores maxStoresPerMemmoveOptSize = Subtarget->isTargetDarwin() ? 8 : 4; - setPrefLoopAlignment(16); + setPrefLoopAlignment(4); // 2^4 bytes. benefitFromCodePlacementOpt = true; - setPrefFunctionAlignment(4); + setPrefFunctionAlignment(4); // 2^4 bytes. } -- 2.34.1