[PATCH] D42737: [LegalizeDAG] Support expanding condition operand of ISD::SELECT

[Eugene Leviant via Phabricator via llvm-commits]

evgeny777 created this revision.
evgeny777 added reviewers: t.p.northover, baldrick, delena, craig.topper, deadalnix.
Herald added subscribers: kristof.beyls, javed.absar, aemerson.

I'm facing a crash when compiling large in-house project for AArch64 using clang, which happens because condition argument of ISD::SELECT can't be expanded (for my case required expansion is `i128 -> i64`). This patch adds required support.


https://reviews.llvm.org/D42737

Files:
  lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
  lib/CodeGen/SelectionDAG/LegalizeTypes.h
  test/CodeGen/AArch64/expand-select.ll


Index: test/CodeGen/AArch64/expand-select.ll
===================================================================
--- test/CodeGen/AArch64/expand-select.ll
+++ test/CodeGen/AArch64/expand-select.ll
@@ -0,0 +1,13 @@
+; REQUIRES: asserts
+
+; Check that we don't crash
+; RUN: llc -mtriple=aarch64-unknown-linux-gnu -O3 %s -debug-only=selectiondag,legalize-types -o -
+
+define void @foo(i32 %In1, <2 x i128> %In2, <2 x i128> %In3, <2 x i128> *%Out) {
+  %cond = and i32 %In1, 1
+  %cbool = icmp eq i32 %cond, 0
+  %res = select i1 %cbool, <2 x i128> %In2, <2 x i128> %In3
+  store <2 x i128> %res, <2 x i128> *%Out
+ 
+  ret void
+}
Index: lib/CodeGen/SelectionDAG/LegalizeTypes.h
===================================================================
--- lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -375,6 +375,7 @@
   // Integer Operand Expansion.
   bool ExpandIntegerOperand(SDNode *N, unsigned OperandNo);
   SDValue ExpandIntOp_BR_CC(SDNode *N);
+  SDValue ExpandIntOp_SELECT(SDNode *N);
   SDValue ExpandIntOp_SELECT_CC(SDNode *N);
   SDValue ExpandIntOp_SETCC(SDNode *N);
   SDValue ExpandIntOp_SETCCE(SDNode *N);
Index: lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -2902,6 +2902,11 @@
   case ISD::EXTRACT_ELEMENT:   Res = ExpandOp_EXTRACT_ELEMENT(N); break;
   case ISD::INSERT_VECTOR_ELT: Res = ExpandOp_INSERT_VECTOR_ELT(N); break;
   case ISD::SCALAR_TO_VECTOR:  Res = ExpandOp_SCALAR_TO_VECTOR(N); break;
+  case ISD::SELECT:
+    // We expect only condition argument to be expanded
+    assert(OpNo == 0);
+    Res = ExpandIntOp_SELECT(N);
+    break;
   case ISD::SELECT_CC:         Res = ExpandIntOp_SELECT_CC(N); break;
   case ISD::SETCC:             Res = ExpandIntOp_SETCC(N); break;
   case ISD::SETCCE:            Res = ExpandIntOp_SETCCE(N); break;
@@ -3106,6 +3111,13 @@
                                 N->getOperand(4)), 0);
 }
 
+SDValue DAGTypeLegalizer::ExpandIntOp_SELECT(SDNode *N) {
+  SDValue InL, InH;
+  GetExpandedInteger(N->getOperand(0), InL, InH);
+  return DAG.getNode(ISD::SELECT, SDLoc(N), N->getValueType(0), InL,
+                     N->getOperand(1), N->getOperand(2));
+}
+
 SDValue DAGTypeLegalizer::ExpandIntOp_SELECT_CC(SDNode *N) {
   SDValue NewLHS = N->getOperand(0), NewRHS = N->getOperand(1);
   ISD::CondCode CCCode = cast<CondCodeSDNode>(N->getOperand(4))->get();


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