[llvm] r245269 - Revert "Constant propagation after hiting llvm.assume"
Justin Bogner via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 18 00:00:34 PDT 2015
Author: bogner
Date: Tue Aug 18 02:00:34 2015
New Revision: 245269
URL: http://llvm.org/viewvc/llvm-project?rev=245269&view=rev
Log:
Revert "Constant propagation after hiting llvm.assume"
This was also failing bootstrap:
http://lab.llvm.org:8080/green/job/clang-stage2-configure-Rlto_build
This reverts r245265.
Removed:
llvm/trunk/test/Transforms/GVN/assume-equal.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/GVN.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/GVN.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GVN.cpp?rev=245269&r1=245268&r2=245269&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/GVN.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/GVN.cpp Tue Aug 18 02:00:34 2015
@@ -608,10 +608,6 @@ namespace {
DenseMap<uint32_t, LeaderTableEntry> LeaderTable;
BumpPtrAllocator TableAllocator;
- // Block-local map of equivalent values to their leader, does not
- // propagate to any successors. Entries added mid-block are applied
- // to the remaining instructions in the block.
- SmallMapVector<llvm::Value *, llvm::Constant *, 4> ReplaceWithConstMap;
SmallVector<Instruction*, 8> InstrsToErase;
typedef SmallVector<NonLocalDepResult, 64> LoadDepVect;
@@ -703,7 +699,6 @@ namespace {
// Helper functions of redundant load elimination
bool processLoad(LoadInst *L);
bool processNonLocalLoad(LoadInst *L);
- bool processAssumeIntrinsic(IntrinsicInst *II);
void AnalyzeLoadAvailability(LoadInst *LI, LoadDepVect &Deps,
AvailValInBlkVect &ValuesPerBlock,
UnavailBlkVect &UnavailableBlocks);
@@ -724,7 +719,6 @@ namespace {
void verifyRemoved(const Instruction *I) const;
bool splitCriticalEdges();
BasicBlock *splitCriticalEdges(BasicBlock *Pred, BasicBlock *Succ);
- bool replaceOperandsWithConsts(Instruction *I) const;
bool propagateEquality(Value *LHS, Value *RHS, const BasicBlockEdge &Root);
bool processFoldableCondBr(BranchInst *BI);
void addDeadBlock(BasicBlock *BB);
@@ -1765,38 +1759,6 @@ bool GVN::processNonLocalLoad(LoadInst *
return PerformLoadPRE(LI, ValuesPerBlock, UnavailableBlocks);
}
-bool GVN::processAssumeIntrinsic(IntrinsicInst *IntrinsicI) {
- assert(IntrinsicI->getIntrinsicID() == Intrinsic::assume &&
- "This function can only be called with llvm.assume intrinsic");
- Value *V = IntrinsicI->getArgOperand(0);
- Constant *True = ConstantInt::getTrue(V->getContext());
- bool Changed = false;
- for (BasicBlock *Successor : successors(IntrinsicI->getParent())) {
- BasicBlockEdge Edge(IntrinsicI->getParent(), Successor);
-
- // This property is only true in dominated successors, propagateEquality
- // will check dominance for us.
- Changed |= propagateEquality(V, True, Edge);
- }
-
- if (auto *CmpI = dyn_cast<CmpInst>(V)) {
- if (CmpI->getPredicate() == CmpInst::Predicate::ICMP_EQ ||
- CmpI->getPredicate() == CmpInst::Predicate::FCMP_OEQ ||
- (CmpI->getPredicate() == CmpInst::Predicate::FCMP_UEQ &&
- CmpI->getFastMathFlags().noNaNs())) {
- Value *CmpLHS = CmpI->getOperand(0);
- Value *CmpRHS = CmpI->getOperand(1);
- if (isa<Constant>(CmpLHS))
- std::swap(CmpLHS, CmpRHS);
- auto *RHSConst = dyn_cast<Constant>(CmpRHS);
-
- // If only one operand is constant.
- if (RHSConst != nullptr && !isa<Constant>(CmpLHS))
- ReplaceWithConstMap[CmpLHS] = RHSConst;
- }
- }
- return Changed;
-}
static void patchReplacementInstruction(Instruction *I, Value *Repl) {
// Patch the replacement so that it is not more restrictive than the value
@@ -2069,21 +2031,6 @@ static bool isOnlyReachableViaThisEdge(c
return Pred != nullptr;
}
-// Tries to replace instruction with const, using information from
-// ReplaceWithConstMap.
-bool GVN::replaceOperandsWithConsts(Instruction *Instr) const {
- bool Changed = false;
- for (unsigned OpNum = 0; OpNum < Instr->getNumOperands(); ++OpNum) {
- Value *Operand = Instr->getOperand(OpNum);
- auto it = ReplaceWithConstMap.find(Operand);
- if (it != ReplaceWithConstMap.end()) {
- Instr->setOperand(OpNum, it->second);
- Changed = true;
- }
- }
- return Changed;
-}
-
/// The given values are known to be equal in every block
/// dominated by 'Root'. Exploit this, for example by replacing 'LHS' with
/// 'RHS' everywhere in the scope. Returns whether a change was made.
@@ -2100,13 +2047,11 @@ bool GVN::propagateEquality(Value *LHS,
std::pair<Value*, Value*> Item = Worklist.pop_back_val();
LHS = Item.first; RHS = Item.second;
- if (LHS == RHS)
- continue;
+ if (LHS == RHS) continue;
assert(LHS->getType() == RHS->getType() && "Equality but unequal types!");
// Don't try to propagate equalities between constants.
- if (isa<Constant>(LHS) && isa<Constant>(RHS))
- continue;
+ if (isa<Constant>(LHS) && isa<Constant>(RHS)) continue;
// Prefer a constant on the right-hand side, or an Argument if no constants.
if (isa<Constant>(LHS) || (isa<Argument>(LHS) && !isa<Constant>(RHS)))
@@ -2257,10 +2202,6 @@ bool GVN::processInstruction(Instruction
return true;
}
- if (IntrinsicInst *IntrinsicI = dyn_cast<IntrinsicInst>(I))
- if (IntrinsicI->getIntrinsicID() == Intrinsic::assume)
- return processAssumeIntrinsic(IntrinsicI);
-
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
if (processLoad(LI))
return true;
@@ -2325,8 +2266,7 @@ bool GVN::processInstruction(Instruction
// Instructions with void type don't return a value, so there's
// no point in trying to find redundancies in them.
- if (I->getType()->isVoidTy())
- return false;
+ if (I->getType()->isVoidTy()) return false;
uint32_t NextNum = VN.getNextUnusedValueNumber();
unsigned Num = VN.lookup_or_add(I);
@@ -2433,15 +2373,10 @@ bool GVN::processBlock(BasicBlock *BB) {
if (DeadBlocks.count(BB))
return false;
- // Clearing map before every BB because it can be used only for single BB.
- ReplaceWithConstMap.clear();
bool ChangedFunction = false;
for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
BI != BE;) {
- if (!ReplaceWithConstMap.empty())
- ChangedFunction |= replaceOperandsWithConsts(BI);
-
ChangedFunction |= processInstruction(BI);
if (InstrsToErase.empty()) {
++BI;
Removed: llvm/trunk/test/Transforms/GVN/assume-equal.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVN/assume-equal.ll?rev=245268&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/GVN/assume-equal.ll (original)
+++ llvm/trunk/test/Transforms/GVN/assume-equal.ll (removed)
@@ -1,122 +0,0 @@
-; RUN: opt < %s -gvn -S | FileCheck %s
-
-%struct.A = type { i32 (...)** }
- at _ZTV1A = available_externally unnamed_addr constant [4 x i8*] [i8* null, i8* bitcast (i8** @_ZTI1A to i8*), i8* bitcast (i32 (%struct.A*)* @_ZN1A3fooEv to i8*), i8* bitcast (i32 (%struct.A*)* @_ZN1A3barEv to i8*)], align 8
- at _ZTI1A = external constant i8*
-
-; Checks if indirect calls can be replaced with direct
-; assuming that %vtable == @_ZTV1A (with alignment).
-; Checking const propagation across other BBs
-; CHECK-LABEL: define void @_Z1gb(
-
-define void @_Z1gb(i1 zeroext %p) {
-entry:
- %call = tail call noalias i8* @_Znwm(i64 8) #4
- %0 = bitcast i8* %call to %struct.A*
- tail call void @_ZN1AC1Ev(%struct.A* %0) #1
- %1 = bitcast i8* %call to i8***
- %vtable = load i8**, i8*** %1, align 8
- %cmp.vtables = icmp eq i8** %vtable, getelementptr inbounds ([4 x i8*], [4 x i8*]* @_ZTV1A, i64 0, i64 2)
- tail call void @llvm.assume(i1 %cmp.vtables)
- br i1 %p, label %if.then, label %if.else
-
-if.then: ; preds = %entry
- %vtable1.cast = bitcast i8** %vtable to i32 (%struct.A*)**
- %2 = load i32 (%struct.A*)*, i32 (%struct.A*)** %vtable1.cast, align 8
-
- ; CHECK: call i32 @_ZN1A3fooEv(
- %call2 = tail call i32 %2(%struct.A* %0) #1
-
- br label %if.end
-
-if.else: ; preds = %entry
- %vfn47 = getelementptr inbounds i8*, i8** %vtable, i64 1
- %vfn4 = bitcast i8** %vfn47 to i32 (%struct.A*)**
-
- ; CHECK: call i32 @_ZN1A3barEv(
- %3 = load i32 (%struct.A*)*, i32 (%struct.A*)** %vfn4, align 8
-
- %call5 = tail call i32 %3(%struct.A* %0) #1
- br label %if.end
-
-if.end: ; preds = %if.else, %if.then
- ret void
-}
-
-; Checking const propagation in the same BB
-; CHECK-LABEL: define i32 @main()
-
-define i32 @main() {
-entry:
- %call = tail call noalias i8* @_Znwm(i64 8)
- %0 = bitcast i8* %call to %struct.A*
- tail call void @_ZN1AC1Ev(%struct.A* %0)
- %1 = bitcast i8* %call to i8***
- %vtable = load i8**, i8*** %1, align 8
- %cmp.vtables = icmp eq i8** %vtable, getelementptr inbounds ([4 x i8*], [4 x i8*]* @_ZTV1A, i64 0, i64 2)
- tail call void @llvm.assume(i1 %cmp.vtables)
- %vtable1.cast = bitcast i8** %vtable to i32 (%struct.A*)**
-
- ; CHECK: call i32 @_ZN1A3fooEv(
- %2 = load i32 (%struct.A*)*, i32 (%struct.A*)** %vtable1.cast, align 8
-
- %call2 = tail call i32 %2(%struct.A* %0)
- ret i32 0
-}
-
-; This tests checks const propatation with fcmp instruction.
-; CHECK-LABEL: define float @_Z1gf(float %p)
-
-define float @_Z1gf(float %p) {
-entry:
- %p.addr = alloca float, align 4
- %f = alloca float, align 4
- store float %p, float* %p.addr, align 4
-
- store float 3.000000e+00, float* %f, align 4
- %0 = load float, float* %p.addr, align 4
- %1 = load float, float* %f, align 4
- %cmp = fcmp oeq float %1, %0 ; note const on lhs
- call void @llvm.assume(i1 %cmp)
-
- ; CHECK: ret float 3.000000e+00
- ret float %0
-}
-
-; CHECK-LABEL: define float @_Z1hf(float %p)
-
-define float @_Z1hf(float %p) {
-entry:
- %p.addr = alloca float, align 4
- store float %p, float* %p.addr, align 4
-
- %0 = load float, float* %p.addr, align 4
- %cmp = fcmp nnan ueq float %0, 3.000000e+00
- call void @llvm.assume(i1 %cmp)
-
- ; CHECK: ret float 3.000000e+00
- ret float %0
-}
-
-; CHECK-LABEL: define float @_Z1if(float %p)
-
-
-define float @_Z1if(float %p) {
-entry:
- %p.addr = alloca float, align 4
- store float %p, float* %p.addr, align 4
-
- %0 = load float, float* %p.addr, align 4
- %cmp = fcmp ueq float %0, 3.000000e+00 ; no nnan flag - can't propagate
- call void @llvm.assume(i1 %cmp)
-
- ; CHECK-NOT: ret float 3.000000e+00
- ret float %0
-}
-
-declare noalias i8* @_Znwm(i64)
-declare void @_ZN1AC1Ev(%struct.A*)
-declare void @llvm.assume(i1)
-declare i32 @_ZN1A3fooEv(%struct.A*)
-declare i32 @_ZN1A3barEv(%struct.A*)
-
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