[llvm] e4fa2e3 - [DAG] isGuaranteedNotToBeUndefOrPoisonForTargetNode - add fallback implementation (#86125)
via llvm-commits
llvm-commits at lists.llvm.org
Thu Mar 21 08:12:02 PDT 2024
Author: Simon Pilgrim
Date: 2024-03-21T15:11:59Z
New Revision: e4fa2e3562f20106f0fe4a4d09df03a548db4eae
URL: https://github.com/llvm/llvm-project/commit/e4fa2e3562f20106f0fe4a4d09df03a548db4eae
DIFF: https://github.com/llvm/llvm-project/commit/e4fa2e3562f20106f0fe4a4d09df03a548db4eae.diff
LOG: [DAG] isGuaranteedNotToBeUndefOrPoisonForTargetNode - add fallback implementation (#86125)
Allow targets to rely on TargetLowering::isGuaranteedNotToBeUndefOrPoisonForTargetNode to test nodes for canCreateUndefOrPoisonForTargetNode + all arguments are isGuaranteedNotToBeUndefOrPoison.
Targets can still perform this themselves for specific special case nodes (e.g. target shuffles).
Matches the fallback in SelectionDAG::isGuaranteedNotToBeUndefOrPoison
Added:
Modified:
llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
Removed:
################################################################################
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 9d73a42df2a479..cd6f083243d09c 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -5042,8 +5042,9 @@ bool SelectionDAG::isGuaranteedNotToBeUndefOrPoison(SDValue Op,
// If Op can't create undef/poison and none of its operands are undef/poison
// then Op is never undef/poison.
- // NOTE: TargetNodes should handle this in themselves in
- // isGuaranteedNotToBeUndefOrPoisonForTargetNode.
+ // NOTE: TargetNodes can handle this in themselves in
+ // isGuaranteedNotToBeUndefOrPoisonForTargetNode or let
+ // TargetLowering::isGuaranteedNotToBeUndefOrPoisonForTargetNode handle it.
return !canCreateUndefOrPoison(Op, PoisonOnly, /*ConsiderFlags*/ true,
Depth) &&
all_of(Op->ops(), [&](SDValue V) {
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 57f8fc409de453..da29b1d5b312f8 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -3786,7 +3786,15 @@ bool TargetLowering::isGuaranteedNotToBeUndefOrPoisonForTargetNode(
Op.getOpcode() == ISD::INTRINSIC_VOID) &&
"Should use isGuaranteedNotToBeUndefOrPoison if you don't know whether Op"
" is a target node!");
- return false;
+
+ // If Op can't create undef/poison and none of its operands are undef/poison
+ // then Op is never undef/poison.
+ return !canCreateUndefOrPoisonForTargetNode(Op, DemandedElts, DAG, PoisonOnly,
+ /*ConsiderFlags*/ true, Depth) &&
+ all_of(Op->ops(), [&](SDValue V) {
+ return DAG.isGuaranteedNotToBeUndefOrPoison(V, PoisonOnly,
+ Depth + 1);
+ });
}
bool TargetLowering::canCreateUndefOrPoisonForTargetNode(
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