[PATCH] D75224: [SelectionDAG][FPEnv] Take into account SelectionDAG continuous CSE when setting the nofpexcept flag for constrained intrinsics

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In D75224#1927019 <https://reviews.llvm.org/D75224#1927019>, @craig.topper wrote:

> Simpler version to think about. Just let Constrained intrinsics handle their own flags completely, and skip them in the common FMF handling.
>
> @spatel what do you think?


Seems fine to me. Could we do something similar for reductions since we can mistakenly drop flags on those too?



================
Comment at: llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp:1116
   if (auto *FPMO = dyn_cast<FPMathOperator>(&I)) {
-    // Propagate the fast-math-flags of this IR instruction to the DAG node that
-    // maps to this instruction.
-    // TODO: We could handle all flags (nsw, etc) here.
-    // TODO: If an IR instruction maps to >1 node, only the final node will have
-    //       flags set.
-    if (SDNode *Node = getNodeForIRValue(&I)) {
-      SDNodeFlags IncomingFlags;
-      IncomingFlags.copyFMF(*FPMO);
-      if (!Node->getFlags().isDefined())
-        Node->setFlags(IncomingFlags);
-      else
-        Node->intersectFlagsWith(IncomingFlags);
-    }
-  }
-  // Constrained FP intrinsics with fpexcept.ignore should also get
-  // the NoFPExcept flag.
-  if (auto *FPI = dyn_cast<ConstrainedFPIntrinsic>(&I))
-    if (FPI->getExceptionBehavior() == fp::ExceptionBehavior::ebIgnore)
+    // ContrainedFPIntrinsics handle their own FMF.
+    if (!isa<ConstrainedFPIntrinsic>(&I)) {
----------------
typo - 'Constrained'


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  https://reviews.llvm.org/D75224/new/

https://reviews.llvm.org/D75224