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[RISCV] Enable merging of external globals by default (#117880)

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This follows up #115495 by enabling merging of external globals by
default, which had been left as a next step in order to make the
previous change more incremental and so we can more easily narrow down
on any identified regressions.

Enabling merging of external globals matches what Arm does (for non
mach-o targets), though AArch64 doesn't as there were [some
concerns](https://reviews.llvm.org/D61947) it might cause regressions in
some cases.

See https://github.com/llvm/llvm-project/pull/117880 for benchmark figures and discussion.
This commit is contained in:
Alex Bradbury 2024-12-11 16:06:49 +00:00 committed by GitHub
parent 10ad2135ab
commit 3787fbf040
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GPG Key ID: B5690EEEBB952194
6 changed files with 19 additions and 29 deletions
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10
llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
View File

@ -51,13 +51,6 @@ static cl::opt<cl::boolOrDefault>
EnableGlobalMerge("riscv-enable-global-merge", cl::Hidden,
cl::desc("Enable the global merge pass"));
static cl::opt<bool> ForceEnableGlobalMergeExternalGlobals(
"riscv-force-enable-global-merge-external-globals", cl::Hidden,
cl::init(false),
cl::desc(
"If the global merge pass is enabled, force enable global merging of "
"external globals (overriding any logic that might disable it)"));
static cl::opt<bool>
EnableMachineCombiner("riscv-enable-machine-combiner",
cl::desc("Enable the machine combiner pass"),
@ -494,8 +487,7 @@ bool RISCVPassConfig::addPreISel() {
// Investigating and addressing both items are TODO.
addPass(createGlobalMergePass(TM, /* MaxOffset */ 2047,
/* OnlyOptimizeForSize */ false,
/* MergeExternalByDefault */
ForceEnableGlobalMergeExternalGlobals));
/* MergeExternalByDefault */ true));
}
return false;

7
llvm/test/CodeGen/RISCV/global-merge-minsize-smalldata-nonzero.ll
View File

@ -1,8 +1,7 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -mtriple=riscv64 -riscv-force-enable-global-merge-external-globals \
; RUN: -verify-machineinstrs < %s | FileCheck %s -check-prefix=SMALL-DATA
; RUN: llc -mtriple=riscv64 -global-merge-min-data-size=0 \
; RUN: -riscv-force-enable-global-merge-external-globals -verify-machineinstrs < %s \
; RUN: llc -mtriple=riscv64 -verify-machineinstrs < %s \
; RUN: | FileCheck %s -check-prefix=SMALL-DATA
; RUN: llc -mtriple=riscv64 -global-merge-min-data-size=0 -verify-machineinstrs < %s \
; RUN: | FileCheck %s -check-prefix=MINSIZE
@ig1 = internal global i32 0, align 4

7
llvm/test/CodeGen/RISCV/global-merge-minsize-smalldata-zero.ll
View File

@ -1,8 +1,7 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -mtriple=riscv32 -riscv-force-enable-global-merge-external-globals \
; RUN: -verify-machineinstrs < %s | FileCheck %s -check-prefix=SMALL-DATA
; RUN: llc -mtriple=riscv64 -global-merge-min-data-size=5 \
; RUN: -riscv-force-enable-global-merge-external-globals -verify-machineinstrs < %s \
; RUN: llc -mtriple=riscv32 -verify-machineinstrs < %s \
; RUN: | FileCheck %s -check-prefix=SMALL-DATA
; RUN: llc -mtriple=riscv64 -global-merge-min-data-size=5 -verify-machineinstrs < %s \
; RUN: | FileCheck %s -check-prefix=MINSIZE
@ig1 = internal global i32 0, align 4

4
llvm/test/CodeGen/RISCV/global-merge-minsize.ll
View File

@ -1,8 +1,8 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -mtriple=riscv32 -riscv-force-enable-global-merge-external-globals \
; RUN: llc -mtriple=riscv32 \
; RUN: -verify-machineinstrs < %s | FileCheck %s -check-prefix=RV32
; RUN: llc -mtriple=riscv32 -global-merge-min-data-size=5 \
; RUN: -riscv-force-enable-global-merge-external-globals -verify-machineinstrs < %s | FileCheck %s -check-prefix=RV32-MINSIZE
; RUN: -verify-machineinstrs < %s | FileCheck %s -check-prefix=RV32-MINSIZE
@ig1 = internal global i32 0, align 4
@ig2 = internal global i32 0, align 4

8
llvm/test/CodeGen/RISCV/global-merge-offset.ll
View File

@ -1,12 +1,12 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: sed 's/ArrSize/100/g' %s | llc -mtriple=riscv32 \
; RUN: -riscv-force-enable-global-merge-external-globals -verify-machineinstrs | FileCheck %s
; RUN: -verify-machineinstrs | FileCheck %s
; RUN: sed 's/ArrSize/100/g' %s | llc -mtriple=riscv64 \
; RUN: -riscv-force-enable-global-merge-external-globals -verify-machineinstrs | FileCheck %s
; RUN: -verify-machineinstrs | FileCheck %s
; RUN: sed 's/ArrSize/101/g' %s | llc -mtriple=riscv32 \
; RUN: -riscv-force-enable-global-merge-external-globals -verify-machineinstrs | FileCheck %s -check-prefix=CHECK-TOOBIG
; RUN: -verify-machineinstrs | FileCheck %s -check-prefix=CHECK-TOOBIG
; RUN: sed 's/ArrSize/101/g' %s | llc -mtriple=riscv64 \
; RUN: -riscv-force-enable-global-merge-external-globals -verify-machineinstrs | FileCheck %s -check-prefix=CHECK-TOOBIG
; RUN: -verify-machineinstrs | FileCheck %s -check-prefix=CHECK-TOOBIG
; This test demonstrates that the MaxOffset is set correctly for RISC-V by
; constructing an input that is at the limit and comparing.

12
llvm/test/CodeGen/RISCV/global-merge.ll
View File

@ -1,11 +1,11 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -mtriple=riscv32 -verify-machineinstrs < %s | FileCheck %s
; RUN: llc -mtriple=riscv64 -verify-machineinstrs < %s | FileCheck %s
; RUN: llc -mtriple=riscv32 \
; RUN: -riscv-force-enable-global-merge-external-globals -verify-machineinstrs < %s \
; RUN: llc -mtriple=riscv32 -global-merge-on-external=false \
; RUN: -verify-machineinstrs < %s | FileCheck %s
; RUN: llc -mtriple=riscv64 -global-merge-on-external=false \
; RUN: -verify-machineinstrs < %s | FileCheck %s
; RUN: llc -mtriple=riscv32 -verify-machineinstrs < %s \
; RUN: | FileCheck -check-prefix=CHECK-WEXTERN %s
; RUN: llc -mtriple=riscv64 \
; RUN: -riscv-force-enable-global-merge-external-globals -verify-machineinstrs < %s \
; RUN: llc -mtriple=riscv64 -verify-machineinstrs < %s \
; RUN: | FileCheck -check-prefix=CHECK-WEXTERN %s
@ig1 = internal global i32 0, align 4