[PATCH] D92128: [RISCV][LegalizeTypes] Teach type legalizer that it can promote UMIN/UMAX using SExtPromotedInteger if that's better for the target.

[Craig Topper via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGfa0f01a3c0e1: [RISCV][LegalizeTypes] Teach type legalizer that it can promote UMIN/UMAX using… (authored by craig.topper).
Herald added a subscriber: jrtc27.

Changed prior to commit:
  https://reviews.llvm.org/D92128?vs=307698&id=308096#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D92128/new/

https://reviews.llvm.org/D92128

Files:
  llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
  llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
  llvm/test/CodeGen/RISCV/rv64Zbb.ll


Index: llvm/test/CodeGen/RISCV/rv64Zbb.ll
===================================================================
--- llvm/test/CodeGen/RISCV/rv64Zbb.ll
+++ llvm/test/CodeGen/RISCV/rv64Zbb.ll
@@ -856,18 +856,12 @@
 ;
 ; RV64IB-LABEL: minu_i32:
 ; RV64IB:       # %bb.0:
-; RV64IB-NEXT:    zext.w a1, a1
-; RV64IB-NEXT:    zext.w a0, a0
 ; RV64IB-NEXT:    minu a0, a0, a1
-; RV64IB-NEXT:    sext.w a0, a0
 ; RV64IB-NEXT:    ret
 ;
 ; RV64IBB-LABEL: minu_i32:
 ; RV64IBB:       # %bb.0:
-; RV64IBB-NEXT:    zext.w a1, a1
-; RV64IBB-NEXT:    zext.w a0, a0
 ; RV64IBB-NEXT:    minu a0, a0, a1
-; RV64IBB-NEXT:    sext.w a0, a0
 ; RV64IBB-NEXT:    ret
   %cmp = icmp ult i32 %a, %b
   %cond = select i1 %cmp, i32 %a, i32 %b
@@ -908,18 +902,12 @@
 ;
 ; RV64IB-LABEL: maxu_i32:
 ; RV64IB:       # %bb.0:
-; RV64IB-NEXT:    zext.w a1, a1
-; RV64IB-NEXT:    zext.w a0, a0
 ; RV64IB-NEXT:    maxu a0, a0, a1
-; RV64IB-NEXT:    sext.w a0, a0
 ; RV64IB-NEXT:    ret
 ;
 ; RV64IBB-LABEL: maxu_i32:
 ; RV64IBB:       # %bb.0:
-; RV64IBB-NEXT:    zext.w a1, a1
-; RV64IBB-NEXT:    zext.w a0, a0
 ; RV64IBB-NEXT:    maxu a0, a0, a1
-; RV64IBB-NEXT:    sext.w a0, a0
 ; RV64IBB-NEXT:    ret
   %cmp = icmp ugt i32 %a, %b
   %cond = select i1 %cmp, i32 %a, i32 %b
Index: llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -331,6 +331,7 @@
   SDValue PromoteIntRes_SimpleIntBinOp(SDNode *N);
   SDValue PromoteIntRes_ZExtIntBinOp(SDNode *N);
   SDValue PromoteIntRes_SExtIntBinOp(SDNode *N);
+  SDValue PromoteIntRes_UMINUMAX(SDNode *N);
   SDValue PromoteIntRes_SIGN_EXTEND_INREG(SDNode *N);
   SDValue PromoteIntRes_SRA(SDNode *N);
   SDValue PromoteIntRes_SRL(SDNode *N);
Index: llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -82,7 +82,7 @@
   case ISD::SMIN:
   case ISD::SMAX:        Res = PromoteIntRes_SExtIntBinOp(N); break;
   case ISD::UMIN:
-  case ISD::UMAX:        Res = PromoteIntRes_ZExtIntBinOp(N); break;
+  case ISD::UMAX:        Res = PromoteIntRes_UMINUMAX(N); break;
 
   case ISD::SHL:         Res = PromoteIntRes_SHL(N); break;
   case ISD::SIGN_EXTEND_INREG:
@@ -1101,6 +1101,15 @@
                      LHS.getValueType(), LHS, RHS);
 }
 
+SDValue DAGTypeLegalizer::PromoteIntRes_UMINUMAX(SDNode *N) {
+  // It doesn't matter if we sign extend or zero extend in the inputs. So do
+  // whatever is best for the target.
+  SDValue LHS = SExtOrZExtPromotedInteger(N->getOperand(0));
+  SDValue RHS = SExtOrZExtPromotedInteger(N->getOperand(1));
+  return DAG.getNode(N->getOpcode(), SDLoc(N),
+                     LHS.getValueType(), LHS, RHS);
+}
+
 SDValue DAGTypeLegalizer::PromoteIntRes_SRA(SDNode *N) {
   // The input value must be properly sign extended.
   SDValue LHS = SExtPromotedInteger(N->getOperand(0));


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