[llvm] [Mips] Use getSignedConstant() for signed values (PR #116405)

[Nikita Popov via llvm-commits]

https://github.com/nikic created https://github.com/llvm/llvm-project/pull/116405

This also adds a getSignedTargetConstant() helper, as these seem to be fairly common in general.

>From d28c407e5f083770967a52f3bfc1d685bf068b51 Mon Sep 17 00:00:00 2001
From: Nikita Popov <npopov at redhat.com>
Date: Fri, 15 Nov 2024 17:18:09 +0100
Subject: [PATCH] [Mips] Use getSignedConstant() for signed values

This also adds a getSignedTargetConstant() helper, as these
seem to be fairly common in general.
---
 llvm/include/llvm/CodeGen/SelectionDAG.h  |  4 ++++
 llvm/lib/Target/Mips/MipsISelDAGToDAG.h   |  5 +++++
 llvm/lib/Target/Mips/MipsISelLowering.cpp | 14 +++++++-------
 llvm/lib/Target/Mips/MipsInstrInfo.td     |  4 +++-
 4 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/llvm/include/llvm/CodeGen/SelectionDAG.h b/llvm/include/llvm/CodeGen/SelectionDAG.h
index 9035aa3ea31278..2e3507386df309 100644
--- a/llvm/include/llvm/CodeGen/SelectionDAG.h
+++ b/llvm/include/llvm/CodeGen/SelectionDAG.h
@@ -700,6 +700,10 @@ class SelectionDAG {
                             bool isOpaque = false) {
     return getConstant(Val, DL, VT, true, isOpaque);
   }
+  SDValue getSignedTargetConstant(int64_t Val, const SDLoc &DL, EVT VT,
+                                  bool isOpaque = false) {
+    return getSignedConstant(Val, DL, VT, true, isOpaque);
+  }
 
   /// Create a true or false constant of type \p VT using the target's
   /// BooleanContent for type \p OpVT.
diff --git a/llvm/lib/Target/Mips/MipsISelDAGToDAG.h b/llvm/lib/Target/Mips/MipsISelDAGToDAG.h
index 6135f968078542..0411a17b4f0669 100644
--- a/llvm/lib/Target/Mips/MipsISelDAGToDAG.h
+++ b/llvm/lib/Target/Mips/MipsISelDAGToDAG.h
@@ -134,6 +134,11 @@ class MipsDAGToDAGISel : public SelectionDAGISel {
     return CurDAG->getTargetConstant(Imm, SDLoc(Node), Node->getValueType(0));
   }
 
+  inline SDValue getSignedImm(const SDNode *Node, int64_t Imm) {
+    return CurDAG->getSignedTargetConstant(Imm, SDLoc(Node),
+                                           Node->getValueType(0));
+  }
+
   virtual void processFunctionAfterISel(MachineFunction &MF) = 0;
 
   bool SelectInlineAsmMemoryOperand(const SDValue &Op,
diff --git a/llvm/lib/Target/Mips/MipsISelLowering.cpp b/llvm/lib/Target/Mips/MipsISelLowering.cpp
index f1cc9fd958447a..ef2c89f49e875a 100644
--- a/llvm/lib/Target/Mips/MipsISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsISelLowering.cpp
@@ -2362,9 +2362,9 @@ SDValue MipsTargetLowering::lowerVAARG(SDValue Op, SelectionDAG &DAG) const {
         ISD::ADD, DL, VAList.getValueType(), VAList,
         DAG.getConstant(Align.value() - 1, DL, VAList.getValueType()));
 
-    VAList = DAG.getNode(
-        ISD::AND, DL, VAList.getValueType(), VAList,
-        DAG.getConstant(-(int64_t)Align.value(), DL, VAList.getValueType()));
+    VAList = DAG.getNode(ISD::AND, DL, VAList.getValueType(), VAList,
+                         DAG.getSignedConstant(-(int64_t)Align.value(), DL,
+                                               VAList.getValueType()));
   }
 
   // Increment the pointer, VAList, to the next vaarg.
@@ -4291,7 +4291,7 @@ void MipsTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
       EVT Type = Op.getValueType();
       int64_t Val = C->getSExtValue();
       if (isInt<16>(Val)) {
-        Result = DAG.getTargetConstant(Val, DL, Type);
+        Result = DAG.getSignedTargetConstant(Val, DL, Type);
         break;
       }
     }
@@ -4321,7 +4321,7 @@ void MipsTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
       EVT Type = Op.getValueType();
       int64_t Val = C->getSExtValue();
       if ((isInt<32>(Val)) && ((Val & 0xffff) == 0)){
-        Result = DAG.getTargetConstant(Val, DL, Type);
+        Result = DAG.getSignedTargetConstant(Val, DL, Type);
         break;
       }
     }
@@ -4331,7 +4331,7 @@ void MipsTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
       EVT Type = Op.getValueType();
       int64_t Val = C->getSExtValue();
       if ((Val >= -65535) && (Val <= -1)) {
-        Result = DAG.getTargetConstant(Val, DL, Type);
+        Result = DAG.getSignedTargetConstant(Val, DL, Type);
         break;
       }
     }
@@ -4341,7 +4341,7 @@ void MipsTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
       EVT Type = Op.getValueType();
       int64_t Val = C->getSExtValue();
       if ((isInt<15>(Val))) {
-        Result = DAG.getTargetConstant(Val, DL, Type);
+        Result = DAG.getSignedTargetConstant(Val, DL, Type);
         break;
       }
     }
diff --git a/llvm/lib/Target/Mips/MipsInstrInfo.td b/llvm/lib/Target/Mips/MipsInstrInfo.td
index 85e3e78d2a4d8f..557e6a2c72e273 100644
--- a/llvm/lib/Target/Mips/MipsInstrInfo.td
+++ b/llvm/lib/Target/Mips/MipsInstrInfo.td
@@ -1199,7 +1199,9 @@ def HI16 : SDNodeXForm<imm, [{
 }]>;
 
 // Plus 1.
-def Plus1 : SDNodeXForm<imm, [{ return getImm(N, N->getSExtValue() + 1); }]>;
+def Plus1 : SDNodeXForm<imm, [{
+  return getSignedImm(N, N->getSExtValue() + 1);
+}]>;
 
 // Node immediate is zero (e.g. insve.d)
 def immz : PatLeaf<(imm), [{ return N->getSExtValue() == 0; }]>;