[llvm] 4ecfaa6 - [AArch64][GlobalISel] Add better basic legalization for llround. (#168427)
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Tue Nov 18 04:05:07 PST 2025
Author: David Green
Date: 2025-11-18T12:05:02Z
New Revision: 4ecfaa602f56a29ea8acd3fd39cf0cf3958b4dae
URL: https://github.com/llvm/llvm-project/commit/4ecfaa602f56a29ea8acd3fd39cf0cf3958b4dae
DIFF: https://github.com/llvm/llvm-project/commit/4ecfaa602f56a29ea8acd3fd39cf0cf3958b4dae.diff
LOG: [AArch64][GlobalISel] Add better basic legalization for llround. (#168427)
This adds handling for f16 and f128 lround/llround under LP64 targets,
promoting the f16 where needed and using a libcall for f128. This
codegen is now identical to the selection dag version.
Added:
Modified:
llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
llvm/test/CodeGen/AArch64/llround-conv-fp16.ll
llvm/test/CodeGen/AArch64/llround-conv.ll
llvm/test/CodeGen/AArch64/lround-conv-fp16.ll
llvm/test/CodeGen/AArch64/lround-conv.ll
Removed:
################################################################################
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index cacb292acee18..ba28e4dda3313 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -3439,6 +3439,18 @@ LegalizerHelper::widenScalar(MachineInstr &MI, unsigned TypeIdx, LLT WideTy) {
Observer.changedInstr(MI);
return Legalized;
}
+ case TargetOpcode::G_LROUND:
+ case TargetOpcode::G_LLROUND:
+ Observer.changingInstr(MI);
+
+ if (TypeIdx == 0)
+ widenScalarDst(MI, WideTy);
+ else
+ widenScalarSrc(MI, WideTy, 1, TargetOpcode::G_FPEXT);
+
+ Observer.changedInstr(MI);
+ return Legalized;
+
case TargetOpcode::G_INTTOPTR:
if (TypeIdx != 1)
return UnableToLegalize;
diff --git a/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp b/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
index a88817c9d2d19..fdf69b04bf676 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
@@ -449,10 +449,12 @@ AArch64LegalizerInfo::AArch64LegalizerInfo(const AArch64Subtarget &ST)
.minScalar(0, s32)
.libcallFor({{s32, s32}, {s64, s32}, {s128, s32}});
- // TODO: Libcall support for s128.
- // TODO: s16 should be legal with full FP16 support.
getActionDefinitionsBuilder({G_LROUND, G_LLROUND})
- .legalFor({{s64, s32}, {s64, s64}});
+ .legalFor({{s64, s32}, {s64, s64}})
+ .legalFor(HasFP16, {{s64, s16}})
+ .minScalar(0, s64)
+ .minScalar(1, s32)
+ .libcallFor({{s64, s128}});
// TODO: Custom legalization for mismatched types.
getActionDefinitionsBuilder(G_FCOPYSIGN)
diff --git a/llvm/test/CodeGen/AArch64/llround-conv-fp16.ll b/llvm/test/CodeGen/AArch64/llround-conv-fp16.ll
index cb042757a4a42..3a4be1bda7cd6 100644
--- a/llvm/test/CodeGen/AArch64/llround-conv-fp16.ll
+++ b/llvm/test/CodeGen/AArch64/llround-conv-fp16.ll
@@ -1,12 +1,8 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 2
; RUN: llc < %s -mtriple=aarch64 | FileCheck %s --check-prefixes=CHECK-NOFP16
; RUN: llc < %s -mtriple=aarch64 -mattr=+fullfp16 | FileCheck %s --check-prefixes=CHECK-FP16
-; RUN: llc < %s -mtriple=aarch64 -global-isel -global-isel-abort=2 2>&1 | FileCheck %s --check-prefixes=CHECK-NOFP16,CHECK-GI
-; RUN: llc < %s -mtriple=aarch64 -mattr=+fullfp16 -global-isel -global-isel-abort=2 2>&1 | FileCheck %s --check-prefixes=CHECK-FP16,CHECK-GI
-
-; CHECK-GI: warning: Instruction selection used fallback path for testmhhs
-; CHECK-GI-NEXT: warning: Instruction selection used fallback path for testmhws
-; CHECK-GI-NEXT: warning: Instruction selection used fallback path for testmhxs
+; RUN: llc < %s -mtriple=aarch64 -global-isel | FileCheck %s --check-prefixes=CHECK-NOFP16
+; RUN: llc < %s -mtriple=aarch64 -mattr=+fullfp16 -global-isel | FileCheck %s --check-prefixes=CHECK-FP16
define i16 @testmhhs(half %x) {
; CHECK-NOFP16-LABEL: testmhhs:
diff --git a/llvm/test/CodeGen/AArch64/llround-conv.ll b/llvm/test/CodeGen/AArch64/llround-conv.ll
index 4cc089804ce97..bdee73076347a 100644
--- a/llvm/test/CodeGen/AArch64/llround-conv.ll
+++ b/llvm/test/CodeGen/AArch64/llround-conv.ll
@@ -1,9 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6
; RUN: llc < %s -mtriple=aarch64 -mattr=+neon | FileCheck %s
-; RUN: llc < %s -mtriple=aarch64 -mattr=+neon -global-isel -global-isel-abort=2 2>&1 | FileCheck %s --check-prefixes=CHECK,CHECK-GI
-
-; CHECK-GI: warning: Instruction selection used fallback path for testmswl
-; CHECK-GI-NEXT: warning: Instruction selection used fallback path for testmsll
+; RUN: llc < %s -mtriple=aarch64 -mattr=+neon -global-isel | FileCheck %s
define i32 @testmsws(float %x) {
; CHECK-LABEL: testmsws:
diff --git a/llvm/test/CodeGen/AArch64/lround-conv-fp16.ll b/llvm/test/CodeGen/AArch64/lround-conv-fp16.ll
index a29dea0eb9f9f..0b18f220067ca 100644
--- a/llvm/test/CodeGen/AArch64/lround-conv-fp16.ll
+++ b/llvm/test/CodeGen/AArch64/lround-conv-fp16.ll
@@ -1,12 +1,8 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 2
; RUN: llc < %s -mtriple=aarch64 | FileCheck %s --check-prefixes=CHECK-NOFP16
; RUN: llc < %s -mtriple=aarch64 -mattr=+fullfp16 | FileCheck %s --check-prefixes=CHECK-FP16
-; RUN: llc < %s -mtriple=aarch64 -global-isel -global-isel-abort=2 2>&1 | FileCheck %s --check-prefixes=CHECK-NOFP16,CHECK-GI
-; RUN: llc < %s -mtriple=aarch64 -mattr=+fullfp16 -global-isel -global-isel-abort=2 2>&1 | FileCheck %s --check-prefixes=CHECK-FP16,CHECK-GI
-
-; CHECK-GI: warning: Instruction selection used fallback path for testmhhs
-; CHECK-GI-NEXT: warning: Instruction selection used fallback path for testmhws
-; CHECK-GI-NEXT: warning: Instruction selection used fallback path for testmhxs
+; RUN: llc < %s -mtriple=aarch64 -global-isel | FileCheck %s --check-prefixes=CHECK-NOFP16
+; RUN: llc < %s -mtriple=aarch64 -mattr=+fullfp16 -global-isel | FileCheck %s --check-prefixes=CHECK-FP16
define i16 @testmhhs(half %x) {
; CHECK-NOFP16-LABEL: testmhhs:
diff --git a/llvm/test/CodeGen/AArch64/lround-conv.ll b/llvm/test/CodeGen/AArch64/lround-conv.ll
index 0bf82b538e70c..4b1782457cc10 100644
--- a/llvm/test/CodeGen/AArch64/lround-conv.ll
+++ b/llvm/test/CodeGen/AArch64/lround-conv.ll
@@ -1,9 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6
; RUN: llc < %s -mtriple=aarch64 -mattr=+neon | FileCheck %s
-; RUN: llc < %s -mtriple=aarch64 -mattr=+neon -global-isel -global-isel-abort=2 2>&1 | FileCheck %s --check-prefixes=CHECK,CHECK-GI
-
-; CHECK-GI: warning: Instruction selection used fallback path for testmswl
-; CHECK-GI-NEXT: warning: Instruction selection used fallback path for testmsll
+; RUN: llc < %s -mtriple=aarch64 -mattr=+neon -global-isel | FileCheck %s
define i32 @testmsws(float %x) {
; CHECK-LABEL: testmsws:
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