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[AArch64][GlobalISel] Enable the localizer for optimized builds. 

Despite the fact that the localizer's original motivation was to fix horrendous
constant spilling at -O0, shortening live ranges still has net benefits even
with optimizations enabled.

On an -Os build of CTMark, doing this improves code size by 0.5% geomean.

There are a few regressions, bullet increasing in size by 0.5%. One example from
bullet where code size increased slightly was due to GlobalISel actually now
generating the same code as SelectionDAG. So we actually have an opportunity
in future to implement better heuristics for localization and therefore be
*better* than SDAG in some cases. In relation to other optimizations though that
one is relatively minor.

Differential Revision: https://reviews.llvm.org/D67303

llvm-svn: 371266
This commit is contained in:
Amara Emerson 2019-09-06 22:27:09 +00:00
parent 7d677adf2d
commit a1cf4d9795
4 changed files with 6 additions and 8 deletions
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4
llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
View File

@ -518,9 +518,7 @@ bool AArch64PassConfig::addRegBankSelect() {
}
void AArch64PassConfig::addPreGlobalInstructionSelect() {
// Workaround the deficiency of the fast register allocator.
if (TM->getOptLevel() == CodeGenOpt::None)
addPass(new Localizer());
addPass(new Localizer());
}
bool AArch64PassConfig::addGlobalInstructionSelect() {

2
llvm/test/CodeGen/AArch64/GlobalISel/gisel-commandline-option.ll
View File

@ -51,7 +51,7 @@
; VERIFY-NEXT: Verify generated machine code
; ENABLED-NEXT: RegBankSelect
; VERIFY-NEXT: Verify generated machine code
; ENABLED-O0-NEXT: Localizer
; ENABLED-NEXT: Localizer
; VERIFY-O0-NEXT: Verify generated machine code
; ENABLED-NEXT: Analysis for ComputingKnownBits
; ENABLED-NEXT: InstructionSelect

6
llvm/test/CodeGen/AArch64/GlobalISel/localizer-in-O0-pipeline.mir
View File

@ -60,18 +60,18 @@ registers:
# Second block will get the constant 1.0 when the localizer is enabled.
# CHECK: bb.1.{{[a-zA-Z0-9]+}}:
# OPT-NOT: G_FCONSTANT
# OPT: [[FONE:%[0-9]+]]:fpr(s32) = G_FCONSTANT float 1.000000e+00
# OPTNONE: [[FONE:%[0-9]+]]:fpr(s32) = G_FCONSTANT float 1.000000e+00
# CHECK: G_BR %bb.3
# Thrid block will get the constant 2.0 when the localizer is enabled.
# CHECK: bb.2.{{[a-zA-Z0-9]+}}:
# OPT-NOT: G_FCONSTANT
# OPT: [[FTWO:%[0-9]+]]:fpr(s32) = G_FCONSTANT float 2.000000e+00
# OPTNONE: [[FTWO:%[0-9]+]]:fpr(s32) = G_FCONSTANT float 2.000000e+00
# CHECK: bb.3.end
# OPTNONE: %2:fpr(s32) = PHI [[FONE]](s32), %bb.1, [[FTWO]](s32), %bb.2
# OPT: %2:fpr(s32) = PHI %4(s32), %bb.1, %5(s32), %bb.2
# OPT: %2:fpr(s32) = PHI [[FONE]](s32), %bb.1, [[FTWO]](s32), %bb.2
# CHECK-NEXT: G_FADD %0, %2
body: |
bb.0 (%ir-block.0):

2
llvm/test/CodeGen/AArch64/GlobalISel/swifterror.ll
View File

@ -98,9 +98,9 @@ handler:
define float @foo_if(%swift_error** swifterror %error_ptr_ref, i32 %cc) {
; CHECK-LABEL: foo_if:
; CHECK: cbz w0
; CHECK: mov [[ID:w[0-9]+]], #1
; CHECK: mov w0, #16
; CHECK: malloc
; CHECK: mov [[ID:w[0-9]+]], #1
; CHECK: strb [[ID]], [x0, #8]
; CHECK: mov x21, x0
; CHECK-NOT: x21