[llvm] 1fa2019 - [SelectionDAG] Add check for BUILD_VECTOR in isKnownNeverNaN

[Petar Avramovic via llvm-commits]

Author: Petar Avramovic
Date: 2022-10-03T12:47:07+02:00
New Revision: 1fa2019828caec1172382009d5327c265427af57

URL: https://github.com/llvm/llvm-project/commit/1fa2019828caec1172382009d5327c265427af57
DIFF: https://github.com/llvm/llvm-project/commit/1fa2019828caec1172382009d5327c265427af57.diff

LOG: [SelectionDAG] Add check for BUILD_VECTOR in isKnownNeverNaN

Includes handling of constants with vector type in isKnownNeverNaN.
For AMDGPU results in not making fcanonicalize during legalization
for vector inputs to fmaxnum_ieee and fminnum_ieee. Does not affect
end result since there is a combine that eliminates fcanonicalize.

Differential Revision: https://reviews.llvm.org/D88573

Added: 
    

Modified: 
    llvm/include/llvm/CodeGen/SelectionDAG.h
    llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

Removed: 
    


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diff  --git a/llvm/include/llvm/CodeGen/SelectionDAG.h b/llvm/include/llvm/CodeGen/SelectionDAG.h
index 6e50b90ef12e7..969199b6f381c 100644
--- a/llvm/include/llvm/CodeGen/SelectionDAG.h
+++ b/llvm/include/llvm/CodeGen/SelectionDAG.h
@@ -2027,9 +2027,9 @@ class SelectionDAG {
   ///     X|Cst == X+Cst iff X&Cst = 0.
   bool isBaseWithConstantOffset(SDValue Op) const;
 
-  /// Test whether the given SDValue is known to never be NaN. If \p SNaN is
-  /// true, returns if \p Op is known to never be a signaling NaN (it may still
-  /// be a qNaN).
+  /// Test whether the given SDValue (or all elements of it, if it is a
+  /// vector) is known to never be NaN. If \p SNaN is true, returns if \p Op is
+  /// known to never be a signaling NaN (it may still be a qNaN).
   bool isKnownNeverNaN(SDValue Op, bool SNaN = false, unsigned Depth = 0) const;
 
   /// \returns true if \p Op is known to never be a signaling NaN.

diff  --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index d866e9d4a1dbb..2da384077013e 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -4683,7 +4683,6 @@ bool SelectionDAG::isKnownNeverNaN(SDValue Op, bool SNaN, unsigned Depth) const
   if (Depth >= MaxRecursionDepth)
     return false; // Limit search depth.
 
-  // TODO: Handle vectors.
   // If the value is a constant, we can obviously see if it is a NaN or not.
   if (const ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(Op)) {
     return !C->getValueAPF().isNaN() ||
@@ -4781,6 +4780,12 @@ bool SelectionDAG::isKnownNeverNaN(SDValue Op, bool SNaN, unsigned Depth) const
   case ISD::EXTRACT_VECTOR_ELT: {
     return isKnownNeverNaN(Op.getOperand(0), SNaN, Depth + 1);
   }
+  case ISD::BUILD_VECTOR: {
+    for (const SDValue &Opnd : Op->ops())
+      if (!isKnownNeverNaN(Opnd, SNaN, Depth + 1))
+        return false;
+    return true;
+  }
   default:
     if (Opcode >= ISD::BUILTIN_OP_END ||
         Opcode == ISD::INTRINSIC_WO_CHAIN ||