[llvm] [ExpandVectorPredication] Be more precise reporting changes (PR #102313)
Roger Ferrer Ibáñez via llvm-commits
llvm-commits at lists.llvm.org
Thu Aug 8 02:19:01 PDT 2024
https://github.com/rofirrim updated https://github.com/llvm/llvm-project/pull/102313
>From 61ccb24a9be3d451dd686e9a79957f54402624c8 Mon Sep 17 00:00:00 2001
From: Roger Ferrer Ibanez <rofirrim at gmail.com>
Date: Tue, 6 Aug 2024 21:13:37 +0200
Subject: [PATCH 1/2] [ExpandVectorPredication] Be more precise reporting
changes
This is used by PreISelIntrinsicLowering. With this change,
PreISelIntrinsicLowering does not have to assume that there were
changes just because we encountered a VP intrinsic.
---
llvm/lib/CodeGen/ExpandVectorPredication.cpp | 41 ++++++++++++-------
llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp | 4 +-
2 files changed, 28 insertions(+), 17 deletions(-)
diff --git a/llvm/lib/CodeGen/ExpandVectorPredication.cpp b/llvm/lib/CodeGen/ExpandVectorPredication.cpp
index 5ffdbcda93e753..dab5958355e068 100644
--- a/llvm/lib/CodeGen/ExpandVectorPredication.cpp
+++ b/llvm/lib/CodeGen/ExpandVectorPredication.cpp
@@ -160,11 +160,15 @@ struct CachingVPExpander {
Value *convertEVLToMask(IRBuilder<> &Builder, Value *EVLParam,
ElementCount ElemCount);
- Value *foldEVLIntoMask(VPIntrinsic &VPI);
+ /// If needed, folds the EVL in the mask operand and discards the EVL
+ /// parameter. Returns a pair of the value of the intrinsic after the change
+ /// (if any) and whether the mask was actually folded.
+ std::pair<Value *, bool> foldEVLIntoMask(VPIntrinsic &VPI);
/// "Remove" the %evl parameter of \p PI by setting it to the static vector
- /// length of the operation.
- void discardEVLParameter(VPIntrinsic &PI);
+ /// length of the operation. Returns true if the %evl (if any) was effectively
+ /// changed.
+ bool discardEVLParameter(VPIntrinsic &PI);
/// Lower this VP binary operator to a unpredicated binary operator.
Value *expandPredicationInBinaryOperator(IRBuilder<> &Builder,
@@ -206,6 +210,9 @@ struct CachingVPExpander {
CachingVPExpander(const TargetTransformInfo &TTI)
: TTI(TTI), UsingTTIOverrides(anyExpandVPOverridesSet()) {}
+ /// Applies the legalization strategy for this intrinsic. Returns true
+ /// if any change happened as part of executing the legalization strategy.
+ /// Returns false if the intrinsic is legal.
bool expandVectorPredication(VPIntrinsic &VPI);
};
@@ -645,15 +652,15 @@ Value *CachingVPExpander::expandPredicationInComparison(IRBuilder<> &Builder,
return NewCmp;
}
-void CachingVPExpander::discardEVLParameter(VPIntrinsic &VPI) {
+bool CachingVPExpander::discardEVLParameter(VPIntrinsic &VPI) {
LLVM_DEBUG(dbgs() << "Discard EVL parameter in " << VPI << "\n");
if (VPI.canIgnoreVectorLengthParam())
- return;
+ return false;
Value *EVLParam = VPI.getVectorLengthParam();
if (!EVLParam)
- return;
+ return false;
ElementCount StaticElemCount = VPI.getStaticVectorLength();
Value *MaxEVL = nullptr;
@@ -672,16 +679,17 @@ void CachingVPExpander::discardEVLParameter(VPIntrinsic &VPI) {
MaxEVL = ConstantInt::get(Int32Ty, StaticElemCount.getFixedValue(), false);
}
VPI.setVectorLengthParam(MaxEVL);
+ return true;
}
-Value *CachingVPExpander::foldEVLIntoMask(VPIntrinsic &VPI) {
+std::pair<Value *, bool> CachingVPExpander::foldEVLIntoMask(VPIntrinsic &VPI) {
LLVM_DEBUG(dbgs() << "Folding vlen for " << VPI << '\n');
IRBuilder<> Builder(&VPI);
// Ineffective %evl parameter and so nothing to do here.
if (VPI.canIgnoreVectorLengthParam())
- return &VPI;
+ return {&VPI, false};
// Only VP intrinsics can have an %evl parameter.
Value *OldMaskParam = VPI.getMaskParam();
@@ -704,7 +712,7 @@ Value *CachingVPExpander::foldEVLIntoMask(VPIntrinsic &VPI) {
"transformation did not render the evl param ineffective!");
// Reassess the modified instruction.
- return &VPI;
+ return {&VPI, true};
}
Value *CachingVPExpander::expandPredication(VPIntrinsic &VPI) {
@@ -812,16 +820,22 @@ bool CachingVPExpander::expandVectorPredication(VPIntrinsic &VPI) {
auto Strategy = getVPLegalizationStrategy(VPI);
sanitizeStrategy(VPI, Strategy);
+ bool Changed = false;
+
// Transform the EVL parameter.
switch (Strategy.EVLParamStrategy) {
case VPLegalization::Legal:
break;
case VPLegalization::Discard:
- discardEVLParameter(VPI);
+ if (discardEVLParameter(VPI))
+ Changed = true;
break;
case VPLegalization::Convert:
- if (foldEVLIntoMask(VPI))
+ if (auto [NewVPI, Folded] = foldEVLIntoMask(VPI); Folded) {
+ (void)NewVPI;
+ Changed = true;
++NumFoldedVL;
+ }
break;
}
@@ -834,13 +848,12 @@ bool CachingVPExpander::expandVectorPredication(VPIntrinsic &VPI) {
case VPLegalization::Convert:
if (Value *V = expandPredication(VPI); V != &VPI) {
++NumLoweredVPOps;
- // Return true if and only if the intrinsic was actually removed.
- return true;
+ Changed = true;
}
break;
}
- return false;
+ return Changed;
}
} // namespace
diff --git a/llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp b/llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
index 0d3dd650b8ee68..6418c54f0b18f0 100644
--- a/llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
+++ b/llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
@@ -357,14 +357,12 @@ bool PreISelIntrinsicLowering::lowerIntrinsics(Module &M) const {
#define BEGIN_REGISTER_VP_INTRINSIC(VPID, MASKPOS, VLENPOS) \
case Intrinsic::VPID:
#include "llvm/IR/VPIntrinsics.def"
- forEachCall(F, [&](CallInst *CI) {
+ Changed |= forEachCall(F, [&](CallInst *CI) {
Function *Parent = CI->getParent()->getParent();
const TargetTransformInfo &TTI = LookupTTI(*Parent);
auto *VPI = cast<VPIntrinsic>(CI);
return expandVectorPredicationIntrinsic(*VPI, TTI);
});
- // Not all intrinsics are removed, but the code is changed in any case.
- Changed = true;
break;
case Intrinsic::objc_autorelease:
Changed |= lowerObjCCall(F, "objc_autorelease");
>From c5d50bf7bb3724b9868cecb7598b8ca26ee2598b Mon Sep 17 00:00:00 2001
From: Roger Ferrer Ibanez <roger.ferrer at bsc.es>
Date: Thu, 8 Aug 2024 09:18:28 +0000
Subject: [PATCH 2/2] [ExpandVectorPredication] Return details about the kind
of expansion
This way PreISelIntrinsicLowering can know whether the intrinsic
was effectively removed or just updated.
---
.../llvm/CodeGen/ExpandVectorPredication.h | 19 +++++++++++----
llvm/lib/CodeGen/ExpandVectorPredication.cpp | 24 +++++++++----------
llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp | 10 ++++++--
3 files changed, 35 insertions(+), 18 deletions(-)
diff --git a/llvm/include/llvm/CodeGen/ExpandVectorPredication.h b/llvm/include/llvm/CodeGen/ExpandVectorPredication.h
index c42c644c99e91e..3aafb22eab6bea 100644
--- a/llvm/include/llvm/CodeGen/ExpandVectorPredication.h
+++ b/llvm/include/llvm/CodeGen/ExpandVectorPredication.h
@@ -16,10 +16,21 @@ namespace llvm {
class TargetTransformInfo;
class VPIntrinsic;
-/// Expand a vector predication intrinsic. Returns true if the intrinsic was
-/// removed/replaced.
-bool expandVectorPredicationIntrinsic(VPIntrinsic &VPI,
- const TargetTransformInfo &TTI);
+/// Represents the details the expansion of a VP intrinsic.
+enum class VPExpansionDetails {
+ /// No change happened during expansion.
+ IntrinsicUnchanged,
+ /// At least one operand was updated.
+ IntrinsicUpdated,
+ /// The whole intrinsic was replaced.
+ IntrinsicReplaced,
+};
+
+/// Expand a vector predication intrinsic. Returns the kind of expansion
+/// that was applied to the intrinsic.
+VPExpansionDetails
+expandVectorPredicationIntrinsic(VPIntrinsic &VPI,
+ const TargetTransformInfo &TTI);
} // end namespace llvm
diff --git a/llvm/lib/CodeGen/ExpandVectorPredication.cpp b/llvm/lib/CodeGen/ExpandVectorPredication.cpp
index dab5958355e068..675d88d6d38cd9 100644
--- a/llvm/lib/CodeGen/ExpandVectorPredication.cpp
+++ b/llvm/lib/CodeGen/ExpandVectorPredication.cpp
@@ -210,10 +210,9 @@ struct CachingVPExpander {
CachingVPExpander(const TargetTransformInfo &TTI)
: TTI(TTI), UsingTTIOverrides(anyExpandVPOverridesSet()) {}
- /// Applies the legalization strategy for this intrinsic. Returns true
- /// if any change happened as part of executing the legalization strategy.
- /// Returns false if the intrinsic is legal.
- bool expandVectorPredication(VPIntrinsic &VPI);
+ /// Expand llvm.vp.* intrinsics as requested by \p TTI.
+ /// Returns the details of the expansion.
+ VPExpansionDetails expandVectorPredication(VPIntrinsic &VPI);
};
//// CachingVPExpander {
@@ -815,12 +814,12 @@ CachingVPExpander::getVPLegalizationStrategy(const VPIntrinsic &VPI) const {
return VPStrat;
}
-/// Expand llvm.vp.* intrinsics as requested by \p TTI.
-bool CachingVPExpander::expandVectorPredication(VPIntrinsic &VPI) {
+VPExpansionDetails
+CachingVPExpander::expandVectorPredication(VPIntrinsic &VPI) {
auto Strategy = getVPLegalizationStrategy(VPI);
sanitizeStrategy(VPI, Strategy);
- bool Changed = false;
+ VPExpansionDetails Changed = VPExpansionDetails::IntrinsicUnchanged;
// Transform the EVL parameter.
switch (Strategy.EVLParamStrategy) {
@@ -828,12 +827,12 @@ bool CachingVPExpander::expandVectorPredication(VPIntrinsic &VPI) {
break;
case VPLegalization::Discard:
if (discardEVLParameter(VPI))
- Changed = true;
+ Changed = VPExpansionDetails::IntrinsicUpdated;
break;
case VPLegalization::Convert:
if (auto [NewVPI, Folded] = foldEVLIntoMask(VPI); Folded) {
(void)NewVPI;
- Changed = true;
+ Changed = VPExpansionDetails::IntrinsicUpdated;
++NumFoldedVL;
}
break;
@@ -848,7 +847,7 @@ bool CachingVPExpander::expandVectorPredication(VPIntrinsic &VPI) {
case VPLegalization::Convert:
if (Value *V = expandPredication(VPI); V != &VPI) {
++NumLoweredVPOps;
- Changed = true;
+ Changed = VPExpansionDetails::IntrinsicReplaced;
}
break;
}
@@ -857,7 +856,8 @@ bool CachingVPExpander::expandVectorPredication(VPIntrinsic &VPI) {
}
} // namespace
-bool llvm::expandVectorPredicationIntrinsic(VPIntrinsic &VPI,
- const TargetTransformInfo &TTI) {
+VPExpansionDetails
+llvm::expandVectorPredicationIntrinsic(VPIntrinsic &VPI,
+ const TargetTransformInfo &TTI) {
return CachingVPExpander(TTI).expandVectorPredication(VPI);
}
diff --git a/llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp b/llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
index 6418c54f0b18f0..9626e785086982 100644
--- a/llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
+++ b/llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
@@ -357,11 +357,17 @@ bool PreISelIntrinsicLowering::lowerIntrinsics(Module &M) const {
#define BEGIN_REGISTER_VP_INTRINSIC(VPID, MASKPOS, VLENPOS) \
case Intrinsic::VPID:
#include "llvm/IR/VPIntrinsics.def"
- Changed |= forEachCall(F, [&](CallInst *CI) {
+ forEachCall(F, [&](CallInst *CI) {
Function *Parent = CI->getParent()->getParent();
const TargetTransformInfo &TTI = LookupTTI(*Parent);
auto *VPI = cast<VPIntrinsic>(CI);
- return expandVectorPredicationIntrinsic(*VPI, TTI);
+ VPExpansionDetails ED = expandVectorPredicationIntrinsic(*VPI, TTI);
+ // Expansion of VP intrinsics may change the IR but not actually
+ // replace the intrinsic, so update Changed for the pass
+ // and compute Removed for forEachCall.
+ Changed |= ED != VPExpansionDetails::IntrinsicUnchanged;
+ bool Removed = ED == VPExpansionDetails::IntrinsicReplaced;
+ return Removed;
});
break;
case Intrinsic::objc_autorelease:
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