[llvm] a4e8347 - AMDGPU: Refactor isConstantCostlierToNegate

[Matt Arsenault via llvm-commits]

Author: Matt Arsenault
Date: 2023-02-15T05:21:00-04:00
New Revision: a4e8347b36617ed81accbf5c5fb3b532db941f4f

URL: https://github.com/llvm/llvm-project/commit/a4e8347b36617ed81accbf5c5fb3b532db941f4f
DIFF: https://github.com/llvm/llvm-project/commit/a4e8347b36617ed81accbf5c5fb3b532db941f4f.diff

LOG: AMDGPU: Refactor isConstantCostlierToNegate

Added: 
    

Modified: 
    llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
    llvm/lib/Target/AMDGPU/AMDGPUISelLowering.h

Removed: 
    


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diff  --git a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
index 35584681a6ba..58a53f1f939d 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
@@ -3844,15 +3844,20 @@ static bool isInv2Pi(const APFloat &APF) {
 
 // 0 and 1.0 / (0.5 * pi) do not have inline immmediates, so there is an
 // additional cost to negate them.
-bool AMDGPUTargetLowering::isConstantCostlierToNegate(SDValue N) const {
-  if (const ConstantFPSDNode *C = isConstOrConstSplatFP(N)) {
-    if (C->isZero() && !C->isNegative())
-      return true;
+TargetLowering::NegatibleCost
+AMDGPUTargetLowering::getConstantNegateCost(const ConstantFPSDNode *C) const {
+  if (C->isZero())
+    return C->isNegative() ? NegatibleCost::Cheaper : NegatibleCost::Expensive;
 
-    if (Subtarget->hasInv2PiInlineImm() && isInv2Pi(C->getValueAPF()))
-      return true;
-  }
+  if (Subtarget->hasInv2PiInlineImm() && isInv2Pi(C->getValueAPF()))
+    return C->isNegative() ? NegatibleCost::Cheaper : NegatibleCost::Expensive;
 
+  return NegatibleCost::Neutral;
+}
+
+bool AMDGPUTargetLowering::isConstantCostlierToNegate(SDValue N) const {
+  if (const ConstantFPSDNode *C = isConstOrConstSplatFP(N))
+    return getConstantNegateCost(C) == NegatibleCost::Expensive;
   return false;
 }
 

diff  --git a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.h b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.h
index 969e4c913853..d7d2c6e65f65 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.h
+++ b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.h
@@ -99,6 +99,9 @@ class AMDGPUTargetLowering : public TargetLowering {
                              SDValue RHS, DAGCombinerInfo &DCI) const;
   SDValue performSelectCombine(SDNode *N, DAGCombinerInfo &DCI) const;
 
+  TargetLowering::NegatibleCost
+  getConstantNegateCost(const ConstantFPSDNode *C) const;
+
   bool isConstantCostlierToNegate(SDValue N) const;
   SDValue performFNegCombine(SDNode *N, DAGCombinerInfo &DCI) const;
   SDValue performFAbsCombine(SDNode *N, DAGCombinerInfo &DCI) const;