[llvm] [AArch64][GlobalISel] SIMD fpcvt codegen for rounding nodes (PR #171446)
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Tue Dec 9 06:20:18 PST 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-globalisel
@llvm/pr-subscribers-backend-aarch64
Author: None (Lukacma)
<details>
<summary>Changes</summary>
This is followup to patch to https://github.com/llvm/llvm-project/pull/165546, which allowed simd fpcvt instructions to be generated from l/llround and l/llrint nodes. This patch extends this work to enable simd fpcvt instruction generation with GlobalISel.
---
Full diff: https://github.com/llvm/llvm-project/pull/171446.diff
6 Files Affected:
- (modified) llvm/lib/Target/AArch64/AArch64InstrInfo.td (+46)
- (modified) llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp (+5-13)
- (modified) llvm/test/CodeGen/AArch64/GlobalISel/regbank-llround.mir (+2-2)
- (modified) llvm/test/CodeGen/AArch64/GlobalISel/regbank-lround.mir (+2-2)
- (modified) llvm/test/CodeGen/AArch64/arm64-cvt-simd-round-rint.ll (+3)
- (modified) llvm/test/CodeGen/AArch64/vector-lrint.ll (+12-6)
``````````diff
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 7ee094ad4ac87..d857199c90173 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -6841,6 +6841,29 @@ defm : FPToIntegerPats<fp_to_uint, fp_to_uint_sat, fp_to_uint_sat_gi, ftrunc, "F
defm : FPToIntegerPats<fp_to_sint, fp_to_sint_sat, fp_to_sint_sat_gi, fround, "FCVTAS">;
defm : FPToIntegerPats<fp_to_uint, fp_to_uint_sat, fp_to_uint_sat_gi, fround, "FCVTAU">;
+// For global-isel we can use register classes to determine
+// which FCVT instruction to use.
+let Predicates = [HasFPRCVT] in {
+def : Pat<(i32 (lround f16:$Rn)),
+ (FCVTASSHr f16:$Rn)>;
+def : Pat<(i32 (lround f64:$Rn)),
+ (FCVTASSDr f64:$Rn)>;
+def : Pat<(i64 (lround f16:$Rn)),
+ (FCVTASDHr f16:$Rn)>;
+def : Pat<(i64 (llround f16:$Rn)),
+ (FCVTASDHr f16:$Rn)>;
+def : Pat<(i64 (lround f32:$Rn)),
+ (FCVTASDSr f32:$Rn)>;
+def : Pat<(i64 (llround f32:$Rn)),
+ (FCVTASDSr f32:$Rn)>;
+}
+def : Pat<(i32 (lround f32:$Rn)),
+ (FCVTASv1i32 f32:$Rn)>;
+def : Pat<(i64 (lround f64:$Rn)),
+ (FCVTASv1i64 f64:$Rn)>;
+def : Pat<(i64 (llround f64:$Rn)),
+ (FCVTASv1i64 f64:$Rn)>;
+
let Predicates = [HasFPRCVT] in {
def : Pat<(f32 (bitconvert (i32 (any_lround f16:$Rn)))),
(FCVTASSHr f16:$Rn)>;
@@ -6862,6 +6885,29 @@ def : Pat<(f64 (bitconvert (i64 (any_lround f64:$Rn)))),
def : Pat<(f64 (bitconvert (i64 (any_llround f64:$Rn)))),
(FCVTASv1i64 f64:$Rn)>;
+// For global-isel we can use register classes to determine
+// which FCVT instruction to use.
+let Predicates = [HasFPRCVT] in {
+def : Pat<(i32 (lrint f16:$Rn)),
+ (FCVTZSSHr (FRINTXHr f16:$Rn))>;
+def : Pat<(i32 (lrint f64:$Rn)),
+ (FCVTZSSDr (FRINTXDr f64:$Rn))>;
+def : Pat<(i64 (lrint f16:$Rn)),
+ (FCVTZSDHr (FRINTXHr f16:$Rn))>;
+def : Pat<(i64 (llrint f16:$Rn)),
+ (FCVTZSDHr (FRINTXHr f16:$Rn))>;
+def : Pat<(i64 (lrint f32:$Rn)),
+ (FCVTZSDSr (FRINTXSr f32:$Rn))>;
+def : Pat<(i64 (llrint f32:$Rn)),
+ (FCVTZSDSr (FRINTXSr f32:$Rn))>;
+}
+def : Pat<(i32 (lrint f32:$Rn)),
+ (FCVTZSv1i32 (FRINTXSr f32:$Rn))>;
+def : Pat<(i64 (lrint f64:$Rn)),
+ (FCVTZSv1i64 (FRINTXDr f64:$Rn))>;
+def : Pat<(i64 (llrint f64:$Rn)),
+ (FCVTZSv1i64 (FRINTXDr f64:$Rn))>;
+
let Predicates = [HasFPRCVT] in {
def : Pat<(f32 (bitconvert (i32 (any_lrint f16:$Rn)))),
(FCVTZSSHr (FRINTXHr f16:$Rn))>;
diff --git a/llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp b/llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp
index 4d3d0811b1524..d646ef8c27881 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp
@@ -867,7 +867,11 @@ AArch64RegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
case TargetOpcode::G_FPTOSI_SAT:
case TargetOpcode::G_FPTOUI_SAT:
case TargetOpcode::G_FPTOSI:
- case TargetOpcode::G_FPTOUI: {
+ case TargetOpcode::G_FPTOUI:
+ case TargetOpcode::G_INTRINSIC_LRINT:
+ case TargetOpcode::G_INTRINSIC_LLRINT:
+ case TargetOpcode::G_LROUND:
+ case TargetOpcode::G_LLROUND: {
LLT DstType = MRI.getType(MI.getOperand(0).getReg());
if (DstType.isVector())
break;
@@ -888,12 +892,6 @@ AArch64RegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
OpRegBankIdx = {PMI_FirstGPR, PMI_FirstFPR};
break;
}
- case TargetOpcode::G_INTRINSIC_LRINT:
- case TargetOpcode::G_INTRINSIC_LLRINT:
- if (MRI.getType(MI.getOperand(0).getReg()).isVector())
- break;
- OpRegBankIdx = {PMI_FirstGPR, PMI_FirstFPR};
- break;
case TargetOpcode::G_FCMP: {
// If the result is a vector, it must use a FPR.
AArch64GenRegisterBankInfo::PartialMappingIdx Idx0 =
@@ -1233,12 +1231,6 @@ AArch64RegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
}
break;
}
- case TargetOpcode::G_LROUND:
- case TargetOpcode::G_LLROUND: {
- // Source is always floating point and destination is always integer.
- OpRegBankIdx = {PMI_FirstGPR, PMI_FirstFPR};
- break;
- }
}
// Finally construct the computed mapping.
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/regbank-llround.mir b/llvm/test/CodeGen/AArch64/GlobalISel/regbank-llround.mir
index 420c7cfb07b74..16100f01017a6 100644
--- a/llvm/test/CodeGen/AArch64/GlobalISel/regbank-llround.mir
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/regbank-llround.mir
@@ -14,7 +14,7 @@ body: |
; CHECK: liveins: $d0
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %fpr:fpr(s64) = COPY $d0
- ; CHECK-NEXT: %llround:gpr(s64) = G_LLROUND %fpr(s64)
+ ; CHECK-NEXT: %llround:fpr(s64) = G_LLROUND %fpr(s64)
; CHECK-NEXT: $d0 = COPY %llround(s64)
; CHECK-NEXT: RET_ReallyLR implicit $s0
%fpr:_(s64) = COPY $d0
@@ -35,7 +35,7 @@ body: |
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %gpr:gpr(s64) = COPY $x0
; CHECK-NEXT: [[COPY:%[0-9]+]]:fpr(s64) = COPY %gpr(s64)
- ; CHECK-NEXT: %llround:gpr(s64) = G_LLROUND [[COPY]](s64)
+ ; CHECK-NEXT: %llround:fpr(s64) = G_LLROUND [[COPY]](s64)
; CHECK-NEXT: $d0 = COPY %llround(s64)
; CHECK-NEXT: RET_ReallyLR implicit $s0
%gpr:_(s64) = COPY $x0
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/regbank-lround.mir b/llvm/test/CodeGen/AArch64/GlobalISel/regbank-lround.mir
index 775c6ca773c68..5cb93f7c4646d 100644
--- a/llvm/test/CodeGen/AArch64/GlobalISel/regbank-lround.mir
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/regbank-lround.mir
@@ -14,7 +14,7 @@ body: |
; CHECK: liveins: $d0
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %fpr:fpr(s64) = COPY $d0
- ; CHECK-NEXT: %lround:gpr(s64) = G_LROUND %fpr(s64)
+ ; CHECK-NEXT: %lround:fpr(s64) = G_LROUND %fpr(s64)
; CHECK-NEXT: $d0 = COPY %lround(s64)
; CHECK-NEXT: RET_ReallyLR implicit $s0
%fpr:_(s64) = COPY $d0
@@ -35,7 +35,7 @@ body: |
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %gpr:gpr(s64) = COPY $x0
; CHECK-NEXT: [[COPY:%[0-9]+]]:fpr(s64) = COPY %gpr(s64)
- ; CHECK-NEXT: %lround:gpr(s64) = G_LROUND [[COPY]](s64)
+ ; CHECK-NEXT: %lround:fpr(s64) = G_LROUND [[COPY]](s64)
; CHECK-NEXT: $d0 = COPY %lround(s64)
; CHECK-NEXT: RET_ReallyLR implicit $s0
%gpr:_(s64) = COPY $x0
diff --git a/llvm/test/CodeGen/AArch64/arm64-cvt-simd-round-rint.ll b/llvm/test/CodeGen/AArch64/arm64-cvt-simd-round-rint.ll
index 8717952ea944a..8da3bfaf09f30 100644
--- a/llvm/test/CodeGen/AArch64/arm64-cvt-simd-round-rint.ll
+++ b/llvm/test/CodeGen/AArch64/arm64-cvt-simd-round-rint.ll
@@ -1,6 +1,9 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
; RUN: llc < %s -mtriple aarch64-unknown-unknown -mattr=+fprcvt,+fullfp16 | FileCheck %s --check-prefixes=CHECK,CHECK-FPRCVT
; RUN: llc < %s -mtriple aarch64-unknown-unknown -mattr=+fullfp16 | FileCheck %s --check-prefixes=CHECK,CHECK-NOFPRCVT
+; RUN: llc < %s -mtriple aarch64-unknown-unknown -global-isel -mattr=+fprcvt,+fullfp16 | FileCheck %s --check-prefixes=CHECK,CHECK-FPRCVT
+; RUN: llc < %s -mtriple aarch64-unknown-unknown -global-isel -mattr=+fullfp16 | FileCheck %s --check-prefixes=CHECK,CHECK-NOFPRCVT
+
;
; Lround
diff --git a/llvm/test/CodeGen/AArch64/vector-lrint.ll b/llvm/test/CodeGen/AArch64/vector-lrint.ll
index 305f8cd67a044..a27a77def1606 100644
--- a/llvm/test/CodeGen/AArch64/vector-lrint.ll
+++ b/llvm/test/CodeGen/AArch64/vector-lrint.ll
@@ -1012,12 +1012,18 @@ define <1 x iXLen> @lrint_v1f64(<1 x double> %x) nounwind {
; CHECK-i32-NEXT: fmov s0, w8
; CHECK-i32-NEXT: ret
;
-; CHECK-i64-LABEL: lrint_v1f64:
-; CHECK-i64: // %bb.0:
-; CHECK-i64-NEXT: frintx d0, d0
-; CHECK-i64-NEXT: fcvtzs x8, d0
-; CHECK-i64-NEXT: fmov d0, x8
-; CHECK-i64-NEXT: ret
+; CHECK-i64-SD-LABEL: lrint_v1f64:
+; CHECK-i64-SD: // %bb.0:
+; CHECK-i64-SD-NEXT: frintx d0, d0
+; CHECK-i64-SD-NEXT: fcvtzs x8, d0
+; CHECK-i64-SD-NEXT: fmov d0, x8
+; CHECK-i64-SD-NEXT: ret
+;
+; CHECK-i64-GI-LABEL: lrint_v1f64:
+; CHECK-i64-GI: // %bb.0:
+; CHECK-i64-GI-NEXT: frintx d0, d0
+; CHECK-i64-GI-NEXT: fcvtzs d0, d0
+; CHECK-i64-GI-NEXT: ret
%a = call <1 x iXLen> @llvm.lrint.v1iXLen.v1f64(<1 x double> %x)
ret <1 x iXLen> %a
}
``````````
</details>
https://github.com/llvm/llvm-project/pull/171446
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