[llvm] [LegalizeVectorOps] Use getBoolConstant instead of getAllOnesConstant in VectorLegalizer::UnrollVSETCC. (PR #121526)

[Craig Topper via llvm-commits]

https://github.com/topperc updated https://github.com/llvm/llvm-project/pull/121526

>From bc6895e9efc9231d39897eea30d52e13272e4c74 Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper at sifive.com>
Date: Thu, 2 Jan 2025 14:35:27 -0800
Subject: [PATCH 1/2] [LegalizeVectorOps] Use getBoolConstant instead of
 getAllOnesConstant in VectorLegalizer::UnrollVSETCC.

This code should follow the target preference for boolean contents
of a vector type. We shouldn't assume that true is negative one.
---
 llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
index db21e708970648..93e081ec9ccc02 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
@@ -2250,7 +2250,8 @@ SDValue VectorLegalizer::UnrollVSETCC(SDNode *Node) {
                          TLI.getSetCCResultType(DAG.getDataLayout(),
                                                 *DAG.getContext(), TmpEltVT),
                          LHSElem, RHSElem, CC);
-    Ops[i] = DAG.getSelect(dl, EltVT, Ops[i], DAG.getAllOnesConstant(dl, EltVT),
+    Ops[i] = DAG.getSelect(dl, EltVT, Ops[i],
+                           DAG.getBoolConstant(true, dl, EltVT, VT),
                            DAG.getConstant(0, dl, EltVT));
   }
   return DAG.getBuildVector(VT, dl, Ops);

>From 1573cfb496a55477411604929595f0f171debaaf Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper at sifive.com>
Date: Fri, 3 Jan 2025 09:23:06 -0800
Subject: [PATCH 2/2] fixup! add FIXME.

---
 llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
index 93e081ec9ccc02..39903bde25a625 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
@@ -2246,6 +2246,7 @@ SDValue VectorLegalizer::UnrollVSETCC(SDNode *Node) {
                                   DAG.getVectorIdxConstant(i, dl));
     SDValue RHSElem = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, TmpEltVT, RHS,
                                   DAG.getVectorIdxConstant(i, dl));
+    // FIXME: We should use i1 setcc + boolext here, but it causes regressions.
     Ops[i] = DAG.getNode(ISD::SETCC, dl,
                          TLI.getSetCCResultType(DAG.getDataLayout(),
                                                 *DAG.getContext(), TmpEltVT),