[llvm] [RISCV] Add vector hasAndNot to enable optimizations (PR #132438)

[Piotr Fusik via llvm-commits]

https://github.com/pfusik created https://github.com/llvm/llvm-project/pull/132438

None

>From 3f6dde9aafd178a18446561266ba541dd6129d21 Mon Sep 17 00:00:00 2001
From: Piotr Fusik <p.fusik at samsung.com>
Date: Fri, 21 Mar 2025 18:24:42 +0100
Subject: [PATCH 1/2] [RISCV][test] Add a test for vector hasAndNot

---
 llvm/test/CodeGen/RISCV/rvv/vandn-sdnode.ll | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/llvm/test/CodeGen/RISCV/rvv/vandn-sdnode.ll b/llvm/test/CodeGen/RISCV/rvv/vandn-sdnode.ll
index a4c64d6fa5ef5..5c24de2fd5601 100644
--- a/llvm/test/CodeGen/RISCV/rvv/vandn-sdnode.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/vandn-sdnode.ll
@@ -2567,3 +2567,24 @@ for.body:
   %exitcond.not = icmp eq i64 %indvars.iv.next, 256
   br i1 %exitcond.not, label %for.cond.cleanup, label %for.body
 }
+
+define <vscale x 1 x i8> @not_signbit_mask_nxv1i8(<vscale x 1 x i8> %a, <vscale x 1 x i8> %b) {
+; CHECK-LABEL: not_signbit_mask_nxv1i8:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    vsetvli a0, zero, e8, mf8, ta, ma
+; CHECK-NEXT:    vmsgt.vi v0, v8, -1
+; CHECK-NEXT:    vmv.v.i v8, 0
+; CHECK-NEXT:    vmerge.vvm v8, v8, v9, v0
+; CHECK-NEXT:    ret
+;
+; CHECK-ZVKB-LABEL: not_signbit_mask_nxv1i8:
+; CHECK-ZVKB:       # %bb.0:
+; CHECK-ZVKB-NEXT:    vsetvli a0, zero, e8, mf8, ta, ma
+; CHECK-ZVKB-NEXT:    vmsgt.vi v0, v8, -1
+; CHECK-ZVKB-NEXT:    vmv.v.i v8, 0
+; CHECK-ZVKB-NEXT:    vmerge.vvm v8, v8, v9, v0
+; CHECK-ZVKB-NEXT:    ret
+  %cond = icmp sgt <vscale x 1 x i8> %a, splat (i8 -1)
+  %r = select <vscale x 1 x i1> %cond, <vscale x 1 x i8> %b, <vscale x 1 x i8> zeroinitializer
+  ret <vscale x 1 x i8> %r
+}

>From 2951c44e3ffdecbb73d94a40c4f0fe442605e474 Mon Sep 17 00:00:00 2001
From: Piotr Fusik <p.fusik at samsung.com>
Date: Fri, 21 Mar 2025 18:14:26 +0100
Subject: [PATCH 2/2] [RISCV] Add vector hasAndNot

---
 llvm/lib/Target/RISCV/RISCVISelLowering.cpp | 10 +++++++++-
 llvm/lib/Target/RISCV/RISCVISelLowering.h   |  1 +
 llvm/test/CodeGen/RISCV/rvv/vandn-sdnode.ll |  6 +++---
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 132faf5b85c1a..97ec9123448a5 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -2051,7 +2051,6 @@ bool RISCVTargetLowering::isMaskAndCmp0FoldingBeneficial(
 bool RISCVTargetLowering::hasAndNotCompare(SDValue Y) const {
   EVT VT = Y.getValueType();
 
-  // FIXME: Support vectors once we have tests.
   if (VT.isVector())
     return false;
 
@@ -2059,6 +2058,15 @@ bool RISCVTargetLowering::hasAndNotCompare(SDValue Y) const {
          (!isa<ConstantSDNode>(Y) || cast<ConstantSDNode>(Y)->isOpaque());
 }
 
+bool RISCVTargetLowering::hasAndNot(SDValue Y) const {
+  EVT VT = Y.getValueType();
+
+  if (!VT.isVector())
+    return hasAndNotCompare(Y);
+
+  return Subtarget.hasStdExtZvkb();
+}
+
 bool RISCVTargetLowering::hasBitTest(SDValue X, SDValue Y) const {
   // Zbs provides BEXT[_I], which can be used with SEQZ/SNEZ as a bit test.
   if (Subtarget.hasStdExtZbs())
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.h b/llvm/lib/Target/RISCV/RISCVISelLowering.h
index ffbc14a29006c..fb3931a561757 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.h
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.h
@@ -535,6 +535,7 @@ class RISCVTargetLowering : public TargetLowering {
   bool isCheapToSpeculateCtlz(Type *Ty) const override;
   bool isMaskAndCmp0FoldingBeneficial(const Instruction &AndI) const override;
   bool hasAndNotCompare(SDValue Y) const override;
+  bool hasAndNot(SDValue Y) const override;
   bool hasBitTest(SDValue X, SDValue Y) const override;
   bool shouldProduceAndByConstByHoistingConstFromShiftsLHSOfAnd(
       SDValue X, ConstantSDNode *XC, ConstantSDNode *CC, SDValue Y,
diff --git a/llvm/test/CodeGen/RISCV/rvv/vandn-sdnode.ll b/llvm/test/CodeGen/RISCV/rvv/vandn-sdnode.ll
index 5c24de2fd5601..319cd94c651aa 100644
--- a/llvm/test/CodeGen/RISCV/rvv/vandn-sdnode.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/vandn-sdnode.ll
@@ -2580,9 +2580,9 @@ define <vscale x 1 x i8> @not_signbit_mask_nxv1i8(<vscale x 1 x i8> %a, <vscale
 ; CHECK-ZVKB-LABEL: not_signbit_mask_nxv1i8:
 ; CHECK-ZVKB:       # %bb.0:
 ; CHECK-ZVKB-NEXT:    vsetvli a0, zero, e8, mf8, ta, ma
-; CHECK-ZVKB-NEXT:    vmsgt.vi v0, v8, -1
-; CHECK-ZVKB-NEXT:    vmv.v.i v8, 0
-; CHECK-ZVKB-NEXT:    vmerge.vvm v8, v8, v9, v0
+; CHECK-ZVKB-NEXT:    vsra.vi v8, v8, 7
+; CHECK-ZVKB-NEXT:    vnot.v v8, v8
+; CHECK-ZVKB-NEXT:    vand.vv v8, v8, v9
 ; CHECK-ZVKB-NEXT:    ret
   %cond = icmp sgt <vscale x 1 x i8> %a, splat (i8 -1)
   %r = select <vscale x 1 x i1> %cond, <vscale x 1 x i8> %b, <vscale x 1 x i8> zeroinitializer