[llvm-commits] [llvm] r85441 - in /llvm/trunk: lib/CodeGen/BranchFolding.cpp test/CodeGen/X86/2008-02-18-TailMergingBug.ll test/CodeGen/X86/2008-05-12-tailmerge-5.ll test/CodeGen/X86/convert-2-addr-3-addr-inc64.ll
Bob Wilson
bob.wilson at apple.com
Wed Oct 28 15:10:21 PDT 2009
Author: bwilson
Date: Wed Oct 28 17:10:20 2009
New Revision: 85441
URL: http://llvm.org/viewvc/llvm-project?rev=85441&view=rev
Log:
Reimplement BranchFolding change to avoid tail merging for a 1 instruction
common tail, except when the OptimizeForSize function attribute is present.
Radar 7338114.
Modified:
llvm/trunk/lib/CodeGen/BranchFolding.cpp
llvm/trunk/test/CodeGen/X86/2008-02-18-TailMergingBug.ll
llvm/trunk/test/CodeGen/X86/2008-05-12-tailmerge-5.ll
llvm/trunk/test/CodeGen/X86/convert-2-addr-3-addr-inc64.ll
Modified: llvm/trunk/lib/CodeGen/BranchFolding.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/BranchFolding.cpp?rev=85441&r1=85440&r2=85441&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/BranchFolding.cpp (original)
+++ llvm/trunk/lib/CodeGen/BranchFolding.cpp Wed Oct 28 17:10:20 2009
@@ -18,6 +18,7 @@
#define DEBUG_TYPE "branchfolding"
#include "BranchFolding.h"
+#include "llvm/Function.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
@@ -465,22 +466,23 @@
CurMPIter!=B && CurMPIter->first==CurHash;
--CurMPIter) {
for (MPIterator I = prior(CurMPIter); I->first==CurHash ; --I) {
- unsigned CommonTailLen = ComputeCommonTailLength(
- CurMPIter->second,
- I->second,
- TrialBBI1, TrialBBI2);
+ unsigned CommonTailLen = ComputeCommonTailLength(CurMPIter->second,
+ I->second,
+ TrialBBI1, TrialBBI2);
// If we will have to split a block, there should be at least
- // minCommonTailLength instructions in common; if not, at worst
- // we will be replacing a fallthrough into the common tail with a
- // branch, which at worst breaks even with falling through into
- // the duplicated common tail, so 1 instruction in common is enough.
- // We will always pick a block we do not have to split as the common
- // tail if there is one.
- // (Empty blocks will get forwarded and need not be considered.)
+ // minCommonTailLength instructions in common. Otherwise, if we are
+ // optimizing for code size, 1 instruction in common is enough. At
+ // worst we will be replacing a fallthrough into the common tail with a
+ // branch, which at worst breaks even with falling through into the
+ // duplicated common tail. We will always pick a block we do not have
+ // to split as the common tail if there is one. (Empty blocks will get
+ // forwarded and need not be considered.)
+ MachineFunction *MF = CurMPIter->second->getParent();
if (CommonTailLen >= minCommonTailLength ||
(CommonTailLen > 0 &&
- (TrialBBI1==CurMPIter->second->begin() ||
- TrialBBI2==I->second->begin()))) {
+ MF->getFunction()->hasFnAttr(Attribute::OptimizeForSize) &&
+ (TrialBBI1 == CurMPIter->second->begin() ||
+ TrialBBI2 == I->second->begin()))) {
if (CommonTailLen > maxCommonTailLength) {
SameTails.clear();
maxCommonTailLength = CommonTailLen;
Modified: llvm/trunk/test/CodeGen/X86/2008-02-18-TailMergingBug.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/2008-02-18-TailMergingBug.ll?rev=85441&r1=85440&r2=85441&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/2008-02-18-TailMergingBug.ll (original)
+++ llvm/trunk/test/CodeGen/X86/2008-02-18-TailMergingBug.ll Wed Oct 28 17:10:20 2009
@@ -3,7 +3,7 @@
@.str = internal constant [48 x i8] c"transformed bounds: (%.2f, %.2f), (%.2f, %.2f)\0A\00" ; <[48 x i8]*> [#uses=1]
-define void @minmax(float* %result) nounwind {
+define void @minmax(float* %result) nounwind optsize {
entry:
%tmp2 = load float* %result, align 4 ; <float> [#uses=6]
%tmp4 = getelementptr float* %result, i32 2 ; <float*> [#uses=5]
Modified: llvm/trunk/test/CodeGen/X86/2008-05-12-tailmerge-5.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/2008-05-12-tailmerge-5.ll?rev=85441&r1=85440&r2=85441&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/2008-05-12-tailmerge-5.ll (original)
+++ llvm/trunk/test/CodeGen/X86/2008-05-12-tailmerge-5.ll Wed Oct 28 17:10:20 2009
@@ -6,7 +6,7 @@
target triple = "x86_64-apple-darwin8"
%struct.BoundaryAlignment = type { [3 x i8], i8, i16, i16, i8, [2 x i8] }
-define void @passing2(i64 %str.0, i64 %str.1, i16 signext %s, i32 %j, i8 signext %c, i16 signext %t, i16 signext %u, i8 signext %d) nounwind {
+define void @passing2(i64 %str.0, i64 %str.1, i16 signext %s, i32 %j, i8 signext %c, i16 signext %t, i16 signext %u, i8 signext %d) nounwind optsize {
entry:
%str_addr = alloca %struct.BoundaryAlignment ; <%struct.BoundaryAlignment*> [#uses=7]
%s_addr = alloca i16 ; <i16*> [#uses=1]
Modified: llvm/trunk/test/CodeGen/X86/convert-2-addr-3-addr-inc64.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/convert-2-addr-3-addr-inc64.ll?rev=85441&r1=85440&r2=85441&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/convert-2-addr-3-addr-inc64.ll (original)
+++ llvm/trunk/test/CodeGen/X86/convert-2-addr-3-addr-inc64.ll Wed Oct 28 17:10:20 2009
@@ -2,7 +2,7 @@
; RUN: grep {asm-printer} | grep {Number of machine instrs printed} | grep 5
; RUN: grep {leal 1(\%rsi),} %t
-define fastcc zeroext i8 @fullGtU(i32 %i1, i32 %i2) nounwind {
+define fastcc zeroext i8 @fullGtU(i32 %i1, i32 %i2) nounwind optsize {
entry:
%0 = add i32 %i2, 1 ; <i32> [#uses=1]
%1 = sext i32 %0 to i64 ; <i64> [#uses=1]
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