[llvm] [RISC] Use hasBEXTILike in useInversedSetcc and shouldFoldSelectWithSingleBitTest. (PR #158366)

[Craig Topper via llvm-commits]

https://github.com/topperc created https://github.com/llvm/llvm-project/pull/158366

Add hasVendorXTHeadCondMov to shouldFoldSelectWithSingleBitTest.

The optimizations in these functions is equally applicable to these.

I changed the RUN line for xtheadcondmove in condops.ll to use XTHeadBs to get converage of the hasBEXTILike changes. I didn't think it was worth an additional RUN line and check prefix.

>From fb4861c19d64653a6e1384076125a4574b5a99c2 Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper at sifive.com>
Date: Fri, 12 Sep 2025 13:13:53 -0700
Subject: [PATCH] [RISC] Use hasBEXTILike in useInversedSetcc and
 shouldFoldSelectWithSingleBitTest.

Add hasVendorXTHeadCondMov to shouldFoldSelectWithSingleBitTest.

The optimizations in these functions is equally applicable to
these.

I changed the RUN line for xtheadcondmove in condops.ll to use
XTHeadBs to get converage of the hasBEXTILike changes. I didn't
think it was worth an additional RUN line and check prefix.
---
 llvm/lib/Target/RISCV/RISCVISelLowering.cpp |  6 +++---
 llvm/test/CodeGen/RISCV/condops.ll          | 19 ++++++++-----------
 2 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 523b857f9e6cd..c3071ad5cd697 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -18950,7 +18950,7 @@ static SDValue useInversedSetcc(SDNode *N, SelectionDAG &DAG,
 
   // Replace (setcc eq (and x, C)) with (setcc ne (and x, C))) to generate
   // BEXTI, where C is power of 2.
-  if (Subtarget.hasStdExtZbs() && VT.isScalarInteger() &&
+  if (Subtarget.hasBEXTILike() && VT.isScalarInteger() &&
       (Subtarget.hasCZEROLike() || Subtarget.hasVendorXTHeadCondMov())) {
     SDValue LHS = Cond.getOperand(0);
     SDValue RHS = Cond.getOperand(1);
@@ -24939,8 +24939,8 @@ RISCVTargetLowering::BuildSDIVPow2(SDNode *N, const APInt &Divisor,
 
 bool RISCVTargetLowering::shouldFoldSelectWithSingleBitTest(
     EVT VT, const APInt &AndMask) const {
-  if (Subtarget.hasCZEROLike())
-    return !Subtarget.hasStdExtZbs() && AndMask.ugt(1024);
+  if (Subtarget.hasCZEROLike() || Subtarget.hasVendorXTHeadCondMov())
+    return !Subtarget.hasBEXTILike() && AndMask.ugt(1024);
   return TargetLowering::shouldFoldSelectWithSingleBitTest(VT, AndMask);
 }
 
diff --git a/llvm/test/CodeGen/RISCV/condops.ll b/llvm/test/CodeGen/RISCV/condops.ll
index 4fb3dff88017c..9d95f1f5c9615 100644
--- a/llvm/test/CodeGen/RISCV/condops.ll
+++ b/llvm/test/CodeGen/RISCV/condops.ll
@@ -3,7 +3,7 @@
 ; RUN: llc -mtriple=riscv64 -target-abi=lp64f -mattr=+f,+zbs < %s | FileCheck %s -check-prefix=RV64I
 ; RUN: llc -mtriple=riscv32 -target-abi=ilp32f -mattr=+f,+zbs,+xventanacondops < %s | FileCheck %s -check-prefix=RV32XVENTANACONDOPS
 ; RUN: llc -mtriple=riscv64 -target-abi=lp64f -mattr=+f,+zbs,+xventanacondops < %s | FileCheck %s -check-prefix=RV64XVENTANACONDOPS
-; RUN: llc -mtriple=riscv64 -target-abi=lp64f -mattr=+f,+zbs,+xtheadcondmov < %s | FileCheck %s -check-prefix=RV64XTHEADCONDMOV
+; RUN: llc -mtriple=riscv64 -target-abi=lp64f -mattr=+f,+xtheadbs,+xtheadcondmov < %s | FileCheck %s -check-prefix=RV64XTHEADCONDMOV
 ; RUN: llc -mtriple=riscv32 -target-abi=ilp32f -mattr=+f,+zbs,+zicond < %s | FileCheck %s -check-prefix=RV32ZICOND
 ; RUN: llc -mtriple=riscv64 -target-abi=lp64f -mattr=+f,+zbs,+zicond < %s | FileCheck %s -check-prefix=RV64ZICOND
 
@@ -126,7 +126,7 @@ define i64 @zero_singlebit1(i64 %rs1, i64 %rs2) {
 ;
 ; RV64XTHEADCONDMOV-LABEL: zero_singlebit1:
 ; RV64XTHEADCONDMOV:       # %bb.0:
-; RV64XTHEADCONDMOV-NEXT:    bexti a1, a1, 12
+; RV64XTHEADCONDMOV-NEXT:    th.tst a1, a1, 12
 ; RV64XTHEADCONDMOV-NEXT:    th.mvnez a0, zero, a1
 ; RV64XTHEADCONDMOV-NEXT:    ret
 ;
@@ -179,9 +179,8 @@ define i64 @zero_singlebit2(i64 %rs1, i64 %rs2) {
 ;
 ; RV64XTHEADCONDMOV-LABEL: zero_singlebit2:
 ; RV64XTHEADCONDMOV:       # %bb.0:
-; RV64XTHEADCONDMOV-NEXT:    slli a1, a1, 51
-; RV64XTHEADCONDMOV-NEXT:    srai a1, a1, 63
-; RV64XTHEADCONDMOV-NEXT:    and a0, a1, a0
+; RV64XTHEADCONDMOV-NEXT:    th.tst a1, a1, 12
+; RV64XTHEADCONDMOV-NEXT:    th.mveqz a0, zero, a1
 ; RV64XTHEADCONDMOV-NEXT:    ret
 ;
 ; RV32ZICOND-LABEL: zero_singlebit2:
@@ -4297,9 +4296,8 @@ define i64 @single_bit(i64 %x) {
 ;
 ; RV64XTHEADCONDMOV-LABEL: single_bit:
 ; RV64XTHEADCONDMOV:       # %bb.0: # %entry
-; RV64XTHEADCONDMOV-NEXT:    slli a1, a0, 53
-; RV64XTHEADCONDMOV-NEXT:    srai a1, a1, 63
-; RV64XTHEADCONDMOV-NEXT:    and a0, a1, a0
+; RV64XTHEADCONDMOV-NEXT:    andi a1, a0, 1024
+; RV64XTHEADCONDMOV-NEXT:    th.mveqz a0, zero, a1
 ; RV64XTHEADCONDMOV-NEXT:    ret
 ;
 ; RV32ZICOND-LABEL: single_bit:
@@ -4353,9 +4351,8 @@ define i64 @single_bit2(i64 %x) {
 ;
 ; RV64XTHEADCONDMOV-LABEL: single_bit2:
 ; RV64XTHEADCONDMOV:       # %bb.0: # %entry
-; RV64XTHEADCONDMOV-NEXT:    slli a1, a0, 52
-; RV64XTHEADCONDMOV-NEXT:    srai a1, a1, 63
-; RV64XTHEADCONDMOV-NEXT:    and a0, a1, a0
+; RV64XTHEADCONDMOV-NEXT:    th.tst a1, a0, 11
+; RV64XTHEADCONDMOV-NEXT:    th.mveqz a0, zero, a1
 ; RV64XTHEADCONDMOV-NEXT:    ret
 ;
 ; RV32ZICOND-LABEL: single_bit2: