[llvm] [X86] Combine LRINT/LLRINT and TRUNC when nuw/nsw (PR #126217)

Phoebe Wang via llvm-commits llvm-commits at lists.llvm.org
Sat Feb 8 01:01:24 PST 2025


https://github.com/phoebewang updated https://github.com/llvm/llvm-project/pull/126217

>From cf29bc411cf4e41c293a174a5ddba27290f128b5 Mon Sep 17 00:00:00 2001
From: "Wang, Phoebe" <phoebe.wang at intel.com>
Date: Fri, 7 Feb 2025 17:59:07 +0800
Subject: [PATCH 1/3] [X86] Combine LRINT/LLRINT and TRUNC when nuw/nsw

Try to improve performance after #125848
---
 llvm/lib/Target/X86/X86ISelLowering.cpp |  5 ++
 llvm/test/CodeGen/X86/llrint-conv.ll    | 88 +++++++++++++++++++++++++
 llvm/test/CodeGen/X86/lrint-conv-i64.ll | 32 +++++++++
 3 files changed, 125 insertions(+)

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 744e4e740cb2102..182cdd90c9d680a 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -53919,6 +53919,11 @@ static SDValue combineTruncate(SDNode *N, SelectionDAG &DAG,
       return DAG.getNode(X86ISD::MMX_MOVD2W, DL, MVT::i32, BCSrc);
   }
 
+  if ((N->getFlags().hasNoUnsignedWrap() || N->getFlags().hasNoSignedWrap()) &&
+      (Src.getOpcode() == ISD::LRINT || Src.getOpcode() == ISD::LLRINT) &&
+      VT.getScalarType() == MVT::i32 && Src.hasOneUse())
+    return DAG.getNode(ISD::LRINT, DL, VT, Src.getOperand(0));
+
   return SDValue();
 }
 
diff --git a/llvm/test/CodeGen/X86/llrint-conv.ll b/llvm/test/CodeGen/X86/llrint-conv.ll
index 402daf80a15e873..2f69824c5f61573 100644
--- a/llvm/test/CodeGen/X86/llrint-conv.ll
+++ b/llvm/test/CodeGen/X86/llrint-conv.ll
@@ -183,6 +183,94 @@ entry:
   ret i64 %0
 }
 
+define i32 @combine_f32_trunc(float %x) nounwind {
+; SSE-LABEL: combine_trunc:
+; SSE:       # %bb.0: # %entry
+; SSE-NEXT:    cvtss2si %xmm0, %eax
+; SSE-NEXT:    retq
+;
+; AVX-LABEL: combine_trunc:
+; AVX:       # %bb.0: # %entry
+; AVX-NEXT:    vcvtss2si %xmm0, %eax
+; AVX-NEXT:    retq
+; X86-NOSSE-LABEL: combine_f32_trunc:
+; X86-NOSSE:       # %bb.0: # %entry
+; X86-NOSSE-NEXT:    pushl %eax
+; X86-NOSSE-NEXT:    flds {{[0-9]+}}(%esp)
+; X86-NOSSE-NEXT:    fistpl (%esp)
+; X86-NOSSE-NEXT:    movl (%esp), %eax
+; X86-NOSSE-NEXT:    popl %ecx
+; X86-NOSSE-NEXT:    retl
+;
+; X86-SSE2-LABEL: combine_f32_trunc:
+; X86-SSE2:       # %bb.0: # %entry
+; X86-SSE2-NEXT:    cvtss2si {{[0-9]+}}(%esp), %eax
+; X86-SSE2-NEXT:    retl
+;
+; X86-AVX-LABEL: combine_f32_trunc:
+; X86-AVX:       # %bb.0: # %entry
+; X86-AVX-NEXT:    vcvtss2si {{[0-9]+}}(%esp), %eax
+; X86-AVX-NEXT:    retl
+;
+; X64-SSE-LABEL: combine_f32_trunc:
+; X64-SSE:       # %bb.0: # %entry
+; X64-SSE-NEXT:    cvtss2si %xmm0, %eax
+; X64-SSE-NEXT:    retq
+;
+; X64-AVX-LABEL: combine_f32_trunc:
+; X64-AVX:       # %bb.0: # %entry
+; X64-AVX-NEXT:    vcvtss2si %xmm0, %eax
+; X64-AVX-NEXT:    retq
+entry:
+  %0 = tail call i64 @llvm.llrint.f32(float %x)
+  %1 = trunc nsw i64 %0 to i32
+  ret i32 %1
+}
+
+define i32 @combine_f64_trunc(double %x) nounwind {
+; SSE-LABEL: combine_trunc:
+; SSE:       # %bb.0: # %entry
+; SSE-NEXT:    cvtss2si %xmm0, %eax
+; SSE-NEXT:    retq
+;
+; AVX-LABEL: combine_trunc:
+; AVX:       # %bb.0: # %entry
+; AVX-NEXT:    vcvtss2si %xmm0, %eax
+; AVX-NEXT:    retq
+; X86-NOSSE-LABEL: combine_f64_trunc:
+; X86-NOSSE:       # %bb.0: # %entry
+; X86-NOSSE-NEXT:    pushl %eax
+; X86-NOSSE-NEXT:    fldl {{[0-9]+}}(%esp)
+; X86-NOSSE-NEXT:    fistpl (%esp)
+; X86-NOSSE-NEXT:    movl (%esp), %eax
+; X86-NOSSE-NEXT:    popl %ecx
+; X86-NOSSE-NEXT:    retl
+;
+; X86-SSE2-LABEL: combine_f64_trunc:
+; X86-SSE2:       # %bb.0: # %entry
+; X86-SSE2-NEXT:    cvtsd2si {{[0-9]+}}(%esp), %eax
+; X86-SSE2-NEXT:    retl
+;
+; X86-AVX-LABEL: combine_f64_trunc:
+; X86-AVX:       # %bb.0: # %entry
+; X86-AVX-NEXT:    vcvtsd2si {{[0-9]+}}(%esp), %eax
+; X86-AVX-NEXT:    retl
+;
+; X64-SSE-LABEL: combine_f64_trunc:
+; X64-SSE:       # %bb.0: # %entry
+; X64-SSE-NEXT:    cvtsd2si %xmm0, %eax
+; X64-SSE-NEXT:    retq
+;
+; X64-AVX-LABEL: combine_f64_trunc:
+; X64-AVX:       # %bb.0: # %entry
+; X64-AVX-NEXT:    vcvtsd2si %xmm0, %eax
+; X64-AVX-NEXT:    retq
+entry:
+  %0 = tail call i64 @llvm.llrint.f64(double %x)
+  %1 = trunc nuw i64 %0 to i32
+  ret i32 %1
+}
+
 declare i64 @llvm.llrint.f32(float) nounwind readnone
 declare i64 @llvm.llrint.f64(double) nounwind readnone
 declare i64 @llvm.llrint.f80(x86_fp80) nounwind readnone
diff --git a/llvm/test/CodeGen/X86/lrint-conv-i64.ll b/llvm/test/CodeGen/X86/lrint-conv-i64.ll
index 38fa09085e1898d..6b9acc02ad7c983 100644
--- a/llvm/test/CodeGen/X86/lrint-conv-i64.ll
+++ b/llvm/test/CodeGen/X86/lrint-conv-i64.ll
@@ -63,6 +63,38 @@ entry:
   ret i32 %1
 }
 
+define i32 @combine_f32_trunc(float %x) {
+; SSE-LABEL: combine_f32_trunc:
+; SSE:       # %bb.0: # %entry
+; SSE-NEXT:    cvtss2si %xmm0, %eax
+; SSE-NEXT:    retq
+;
+; AVX-LABEL: combine_f32_trunc:
+; AVX:       # %bb.0: # %entry
+; AVX-NEXT:    vcvtss2si %xmm0, %eax
+; AVX-NEXT:    retq
+entry:
+  %0 = tail call i64 @llvm.lrint.i64.f32(float %x)
+  %1 = trunc nuw i64 %0 to i32
+  ret i32 %1
+}
+
+define i32 @combine_f64_trunc(double %x) {
+; SSE-LABEL: combine_f64_trunc:
+; SSE:       # %bb.0: # %entry
+; SSE-NEXT:    cvtsd2si %xmm0, %eax
+; SSE-NEXT:    retq
+;
+; AVX-LABEL: combine_f64_trunc:
+; AVX:       # %bb.0: # %entry
+; AVX-NEXT:    vcvtsd2si %xmm0, %eax
+; AVX-NEXT:    retq
+entry:
+  %0 = tail call i64 @llvm.lrint.i64.f64(double %x)
+  %1 = trunc nsw i64 %0 to i32
+  ret i32 %1
+}
+
 declare i64 @llvm.lrint.i64.f32(float) nounwind readnone
 declare i64 @llvm.lrint.i64.f64(double) nounwind readnone
 declare i64 @llvm.lrint.i64.f80(x86_fp80) nounwind readnone

>From 0be125eca93668f942d3d15cfe397277af25c6a2 Mon Sep 17 00:00:00 2001
From: "Wang, Phoebe" <phoebe.wang at intel.com>
Date: Fri, 7 Feb 2025 22:32:11 +0800
Subject: [PATCH 2/3] Clean up check prefixes

---
 llvm/test/CodeGen/X86/llrint-conv.ll | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/llvm/test/CodeGen/X86/llrint-conv.ll b/llvm/test/CodeGen/X86/llrint-conv.ll
index 2f69824c5f61573..de4872716951bc9 100644
--- a/llvm/test/CodeGen/X86/llrint-conv.ll
+++ b/llvm/test/CodeGen/X86/llrint-conv.ll
@@ -184,15 +184,6 @@ entry:
 }
 
 define i32 @combine_f32_trunc(float %x) nounwind {
-; SSE-LABEL: combine_trunc:
-; SSE:       # %bb.0: # %entry
-; SSE-NEXT:    cvtss2si %xmm0, %eax
-; SSE-NEXT:    retq
-;
-; AVX-LABEL: combine_trunc:
-; AVX:       # %bb.0: # %entry
-; AVX-NEXT:    vcvtss2si %xmm0, %eax
-; AVX-NEXT:    retq
 ; X86-NOSSE-LABEL: combine_f32_trunc:
 ; X86-NOSSE:       # %bb.0: # %entry
 ; X86-NOSSE-NEXT:    pushl %eax
@@ -228,15 +219,6 @@ entry:
 }
 
 define i32 @combine_f64_trunc(double %x) nounwind {
-; SSE-LABEL: combine_trunc:
-; SSE:       # %bb.0: # %entry
-; SSE-NEXT:    cvtss2si %xmm0, %eax
-; SSE-NEXT:    retq
-;
-; AVX-LABEL: combine_trunc:
-; AVX:       # %bb.0: # %entry
-; AVX-NEXT:    vcvtss2si %xmm0, %eax
-; AVX-NEXT:    retq
 ; X86-NOSSE-LABEL: combine_f64_trunc:
 ; X86-NOSSE:       # %bb.0: # %entry
 ; X86-NOSSE-NEXT:    pushl %eax

>From d170e8dc70ef758f04eb280f8afcd931e0613eee Mon Sep 17 00:00:00 2001
From: "Wang, Phoebe" <phoebe.wang at intel.com>
Date: Sat, 8 Feb 2025 17:01:07 +0800
Subject: [PATCH 3/3] Add vector tests

---
 llvm/test/CodeGen/X86/vector-llrint.ll | 20 ++++++++++++++++++++
 llvm/test/CodeGen/X86/vector-lrint.ll  | 25 +++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/llvm/test/CodeGen/X86/vector-llrint.ll b/llvm/test/CodeGen/X86/vector-llrint.ll
index 7017eb60df41d67..8414b2ced289276 100644
--- a/llvm/test/CodeGen/X86/vector-llrint.ll
+++ b/llvm/test/CodeGen/X86/vector-llrint.ll
@@ -673,3 +673,23 @@ define <8 x i64> @llrint_v8i64_v8f64(<8 x double> %x) {
   ret <8 x i64> %a
 }
 declare <8 x i64> @llvm.llrint.v8i64.v8f64(<8 x double>)
+
+define <4 x i32> @llrint_v4i32_v4f32(<4 x float> %x) {
+; SSE-LABEL: llrint_v4i32_v4f32:
+; SSE:       # %bb.0:
+; SSE-NEXT:    cvtps2dq %xmm0, %xmm0
+; SSE-NEXT:    retq
+;
+; AVX-LABEL: llrint_v4i32_v4f32:
+; AVX:       # %bb.0:
+; AVX-NEXT:    vcvtps2dq %xmm0, %xmm0
+; AVX-NEXT:    retq
+;
+; AVX512DQ-LABEL: llrint_v4i32_v4f32:
+; AVX512DQ:       # %bb.0:
+; AVX512DQ-NEXT:    vcvtps2dq %xmm0, %xmm0
+; AVX512DQ-NEXT:    retq
+  %a = call <4 x i64> @llvm.llrint.v4i64.v4f32(<4 x float> %x)
+  %b = trunc nsw <4 x i64> %a to <4 x i32>
+  ret <4 x i32> %b
+}
diff --git a/llvm/test/CodeGen/X86/vector-lrint.ll b/llvm/test/CodeGen/X86/vector-lrint.ll
index 3612205bf1bfa9c..a45c500f1199bb1 100644
--- a/llvm/test/CodeGen/X86/vector-lrint.ll
+++ b/llvm/test/CodeGen/X86/vector-lrint.ll
@@ -537,3 +537,28 @@ define <8 x iXLen> @lrint_v8f64(<8 x double> %x) {
   ret <8 x iXLen> %a
 }
 declare <8 x iXLen> @llvm.lrint.v8iXLen.v8f64(<8 x double>)
+
+define <4 x i32> @llrint_v4i32_v4f32(<4 x float> %x) {
+; X86-SSE2-LABEL: llrint_v4i32_v4f32:
+; X86-SSE2:       # %bb.0:
+; X86-SSE2-NEXT:    cvtps2dq %xmm0, %xmm0
+; X86-SSE2-NEXT:    retl
+;
+; X86-AVX-LABEL: llrint_v4i32_v4f32:
+; X86-AVX:       # %bb.0:
+; X86-AVX-NEXT:    vcvtps2dq %xmm0, %xmm0
+; X86-AVX-NEXT:    retl
+;
+; X64-AVX-i32-LABEL: llrint_v4i32_v4f32:
+; X64-AVX-i32:       # %bb.0:
+; X64-AVX-i32-NEXT:    vcvtps2dq %xmm0, %xmm0
+; X64-AVX-i32-NEXT:    retq
+;
+; X64-AVX-i64-LABEL: llrint_v4i32_v4f32:
+; X64-AVX-i64:       # %bb.0:
+; X64-AVX-i64-NEXT:    vcvtps2dq %xmm0, %xmm0
+; X64-AVX-i64-NEXT:    retq
+  %a = call <4 x i64> @llvm.lrint.v4i64.v4f32(<4 x float> %x)
+  %b = trunc nuw <4 x i64> %a to <4 x i32>
+  ret <4 x i32> %b
+}



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