[TargetLowering] Rename preferShiftsToClearExtremeBits and shouldFoldShiftPairToMask...

As discussed on PR41359, this patch renames the pair of shift-mask target feature functions to make their purposes more obvious.

shouldFoldShiftPairToMask -> shouldFoldConstantShiftPairToMask

preferShiftsToClearExtremeBits -> shouldFoldMaskToVariableShiftPair

llvm-svn: 358526

diff --git a/llvm/include/llvm/CodeGen/TargetLowering.h b/llvm/include/llvm/CodeGen/TargetLowering.h
index a5e4196..cbbf1cc 100644 (file)
--- a/llvm/include/llvm/CodeGen/TargetLowering.h
+++ b/llvm/include/llvm/CodeGen/TargetLowering.h
@@ -527,9 +527,9 @@ public:
   /// There are two ways to clear extreme bits (either low or high):
   /// Mask:    x &  (-1 << y)  (the instcombine canonical form)
   /// Shifts:  x >> y << y
-  /// Return true if the variant with 2 shifts is preferred.
+  /// Return true if the variant with 2 variable shifts is preferred.
   /// Return false if there is no preference.
-  virtual bool preferShiftsToClearExtremeBits(SDValue X) const {
+  virtual bool shouldFoldMaskToVariableShiftPair(SDValue X) const {
     // By default, let's assume that no one prefers shifts.
     return false;
   }
@@ -538,8 +538,8 @@ public:
   /// This is usually true on most targets. But some targets, like Thumb1,
   /// have immediate shift instructions, but no immediate "and" instruction;
   /// this makes the fold unprofitable.
-  virtual bool shouldFoldShiftPairToMask(const SDNode *N,
-                                         CombineLevel Level) const {
+  virtual bool shouldFoldConstantShiftPairToMask(const SDNode *N,
+                                                 CombineLevel Level) const {
     return true;
   }
 

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index b03c65c..51f7d73 100644 (file)
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4677,7 +4677,7 @@ SDValue DAGCombiner::unfoldExtremeBitClearingToShifts(SDNode *N) {
   SDValue N1 = N->getOperand(1);
 
   // Do we actually prefer shifts over mask?
-  if (!TLI.preferShiftsToClearExtremeBits(N0))
+  if (!TLI.shouldFoldMaskToVariableShiftPair(N0))
     return SDValue();
 
   // Try to match  (-1 '[outer] logical shift' y)
@@ -6850,7 +6850,7 @@ SDValue DAGCombiner::visitSHL(SDNode *N) {
   // Only fold this if the inner shift has no other uses -- if it does, folding
   // this will increase the total number of instructions.
   if (N1C && N0.getOpcode() == ISD::SRL && N0.hasOneUse() &&
-      TLI.shouldFoldShiftPairToMask(N, Level)) {
+      TLI.shouldFoldConstantShiftPairToMask(N, Level)) {
     if (ConstantSDNode *N0C1 = isConstOrConstSplat(N0.getOperand(1))) {
       if (N0C1->getAPIntValue().ult(OpSizeInBits)) {
         uint64_t c1 = N0C1->getZExtValue();

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index cbf4796..0281d68 100644 (file)
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -10483,9 +10483,8 @@ ARMTargetLowering::isDesirableToCommuteWithShift(const SDNode *N,
   return false;
 }
 
-bool
-ARMTargetLowering::shouldFoldShiftPairToMask(const SDNode *N,
-                                             CombineLevel Level) const {
+bool ARMTargetLowering::shouldFoldConstantShiftPairToMask(
+    const SDNode *N, CombineLevel Level) const {
   if (!Subtarget->isThumb1Only())
     return true;
 

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.h b/llvm/lib/Target/ARM/ARMISelLowering.h
index 9728383..911db14 100644 (file)
--- a/llvm/lib/Target/ARM/ARMISelLowering.h
+++ b/llvm/lib/Target/ARM/ARMISelLowering.h
@@ -598,8 +598,8 @@ class VectorType;
     bool isDesirableToCommuteWithShift(const SDNode *N,
                                        CombineLevel Level) const override;
 
-    bool shouldFoldShiftPairToMask(const SDNode *N,
-                                   CombineLevel Level) const override;
+    bool shouldFoldConstantShiftPairToMask(const SDNode *N,
+                                           CombineLevel Level) const override;
   protected:
     std::pair<const TargetRegisterClass *, uint8_t>
     findRepresentativeClass(const TargetRegisterInfo *TRI,

diff --git a/llvm/lib/Target/Mips/MipsISelLowering.cpp b/llvm/lib/Target/Mips/MipsISelLowering.cpp
index f942d3f..99de079 100644 (file)
--- a/llvm/lib/Target/Mips/MipsISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsISelLowering.cpp
@@ -1190,8 +1190,8 @@ bool MipsTargetLowering::isCheapToSpeculateCtlz() const {
   return Subtarget.hasMips32();
 }
 
-bool MipsTargetLowering::shouldFoldShiftPairToMask(const SDNode *N,
-                                                   CombineLevel Level) const {
+bool MipsTargetLowering::shouldFoldConstantShiftPairToMask(
+    const SDNode *N, CombineLevel Level) const {
   if (N->getOperand(0).getValueType().isVector())
     return false;
   return true;

diff --git a/llvm/lib/Target/Mips/MipsISelLowering.h b/llvm/lib/Target/Mips/MipsISelLowering.h
index 431387b..b93e2c3 100644 (file)
--- a/llvm/lib/Target/Mips/MipsISelLowering.h
+++ b/llvm/lib/Target/Mips/MipsISelLowering.h
@@ -284,8 +284,8 @@ class TargetRegisterClass;
 
     bool isCheapToSpeculateCttz() const override;
     bool isCheapToSpeculateCtlz() const override;
-    bool shouldFoldShiftPairToMask(const SDNode *N,
-                                   CombineLevel Level) const override;
+    bool shouldFoldConstantShiftPairToMask(const SDNode *N,
+                                           CombineLevel Level) const override;
 
     /// Return the register type for a given MVT, ensuring vectors are treated
     /// as a series of gpr sized integers.

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index e379c35..f51d357 100644 (file)
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -5007,7 +5007,7 @@ bool X86TargetLowering::hasAndNot(SDValue Y) const {
   return Subtarget.hasSSE2();
 }
 
-bool X86TargetLowering::preferShiftsToClearExtremeBits(SDValue Y) const {
+bool X86TargetLowering::shouldFoldMaskToVariableShiftPair(SDValue Y) const {
   EVT VT = Y.getValueType();
 
   // For vectors, we don't have a preference, but we probably want a mask.

diff --git a/llvm/lib/Target/X86/X86ISelLowering.h b/llvm/lib/Target/X86/X86ISelLowering.h
index 193d040..1742e74 100644 (file)
--- a/llvm/lib/Target/X86/X86ISelLowering.h
+++ b/llvm/lib/Target/X86/X86ISelLowering.h
@@ -814,7 +814,7 @@ namespace llvm {
 
     bool hasAndNot(SDValue Y) const override;
 
-    bool preferShiftsToClearExtremeBits(SDValue Y) const override;
+    bool shouldFoldMaskToVariableShiftPair(SDValue Y) const override;
 
     bool
     shouldTransformSignedTruncationCheck(EVT XVT,