[llvm] r328312 - Revert r328307: [IPSCCP] Use constant range information for comparisons of parameters.
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Fri Mar 23 05:49:39 PDT 2018
Author: fhahn
Date: Fri Mar 23 05:49:39 2018
New Revision: 328312
URL: http://llvm.org/viewvc/llvm-project?rev=328312&view=rev
Log:
Revert r328307: [IPSCCP] Use constant range information for comparisons of parameters.
Reverted for now, due to it causing verifier failures.
Modified:
llvm/trunk/lib/Transforms/Scalar/SCCP.cpp
llvm/trunk/test/Transforms/SCCP/ip-constant-ranges.ll
Modified: llvm/trunk/lib/Transforms/Scalar/SCCP.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SCCP.cpp?rev=328312&r1=328311&r2=328312&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SCCP.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SCCP.cpp Fri Mar 23 05:49:39 2018
@@ -69,6 +69,8 @@ STATISTIC(NumDeadBlocks , "Number of bas
STATISTIC(IPNumInstRemoved, "Number of instructions removed by IPSCCP");
STATISTIC(IPNumArgsElimed ,"Number of arguments constant propagated by IPSCCP");
STATISTIC(IPNumGlobalConst, "Number of globals found to be constant by IPSCCP");
+STATISTIC(IPNumRangeInfoUsed, "Number of times constant range info was used by"
+ "IPSCCP");
namespace {
@@ -1037,26 +1039,15 @@ void SCCPSolver::visitBinaryOperator(Ins
// Handle ICmpInst instruction.
void SCCPSolver::visitCmpInst(CmpInst &I) {
+ LatticeVal V1State = getValueState(I.getOperand(0));
+ LatticeVal V2State = getValueState(I.getOperand(1));
+
LatticeVal &IV = ValueState[&I];
if (IV.isOverdefined()) return;
- Value *Op1 = I.getOperand(0);
- Value *Op2 = I.getOperand(1);
-
- // For parameters, use ParamState which includes constant range info if
- // available.
- auto V1Param = ParamState.find(Op1);
- ValueLatticeElement V1State = (V1Param != ParamState.end())
- ? V1Param->second
- : getValueState(Op1).toValueLattice();
-
- auto V2Param = ParamState.find(Op2);
- ValueLatticeElement V2State = V2Param != ParamState.end()
- ? V2Param->second
- : getValueState(Op2).toValueLattice();
-
- Constant *C = V1State.getCompare(I.getPredicate(), I.getType(), V2State);
- if (C) {
+ if (V1State.isConstant() && V2State.isConstant()) {
+ Constant *C = ConstantExpr::getCompare(
+ I.getPredicate(), V1State.getConstant(), V2State.getConstant());
if (isa<UndefValue>(C))
return;
return markConstant(IV, &I, C);
@@ -1625,6 +1616,45 @@ bool SCCPSolver::ResolvedUndefsIn(Functi
return false;
}
+static bool tryToReplaceWithConstantRange(SCCPSolver &Solver, Value *V) {
+ bool Changed = false;
+
+ // Currently we only use range information for integer values.
+ if (!V->getType()->isIntegerTy())
+ return false;
+
+ const ValueLatticeElement &IV = Solver.getLatticeValueFor(V);
+ if (!IV.isConstantRange())
+ return false;
+
+ for (auto UI = V->uses().begin(), E = V->uses().end(); UI != E;) {
+ const Use &U = *UI++;
+ auto *Icmp = dyn_cast<ICmpInst>(U.getUser());
+ if (!Icmp || !Solver.isBlockExecutable(Icmp->getParent()))
+ continue;
+
+ auto getIcmpLatticeValue = [&](Value *Op) {
+ if (auto *C = dyn_cast<Constant>(Op))
+ return ValueLatticeElement::get(C);
+ return Solver.getLatticeValueFor(Op);
+ };
+
+ ValueLatticeElement A = getIcmpLatticeValue(Icmp->getOperand(0));
+ ValueLatticeElement B = getIcmpLatticeValue(Icmp->getOperand(1));
+
+ Constant *C = A.getCompare(Icmp->getPredicate(), Icmp->getType(), B);
+ if (C) {
+ Icmp->replaceAllUsesWith(C);
+ DEBUG(dbgs() << "Replacing " << *Icmp << " with " << *C
+ << ", because of range information " << A << " " << B
+ << "\n");
+ Icmp->eraseFromParent();
+ Changed = true;
+ }
+ }
+ return Changed;
+}
+
static bool tryToReplaceWithConstant(SCCPSolver &Solver, Value *V) {
Constant *Const = nullptr;
if (V->getType()->isStructTy()) {
@@ -1893,6 +1923,9 @@ bool llvm::runIPSCCP(Module &M, const Da
++IPNumArgsElimed;
continue;
}
+
+ if (!AI->use_empty() && tryToReplaceWithConstantRange(Solver, &*AI))
+ ++IPNumRangeInfoUsed;
}
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
Modified: llvm/trunk/test/Transforms/SCCP/ip-constant-ranges.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SCCP/ip-constant-ranges.ll?rev=328312&r1=328311&r2=328312&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/SCCP/ip-constant-ranges.ll (original)
+++ llvm/trunk/test/Transforms/SCCP/ip-constant-ranges.ll Fri Mar 23 05:49:39 2018
@@ -2,7 +2,11 @@
; Constant range for %a is [1, 48) and for %b is [301, 1000)
; CHECK-LABEL: f1
-; CHECK: ret i32 undef
+; CHECK-NOT: icmp
+; CHECK: %a.1 = select i1 false, i32 1, i32 2
+; CHECK: %b.1 = select i1 true, i32 1, i32 2
+; CHECK: %a.2 = select i1 false, i32 1, i32 2
+; CHECK: %b.2 = select i1 true, i32 1, i32 2
define internal i32 @f1(i32 %a, i32 %b) {
entry:
%cmp.a = icmp sgt i32 %a, 300
@@ -24,11 +28,10 @@ entry:
; CHECK-LABEL: f2
; CHECK: %cmp = icmp sgt i32 %x, 300
; CHECK: %res1 = select i1 %cmp, i32 1, i32 2
+; CHECK-NEXT: %res2 = select i1 true, i32 3, i32 4
+; CHECK-NEXT: %res3 = select i1 true, i32 5, i32 6
; CHECK-NEXT: %res4 = select i1 %cmp4, i32 3, i32 4
-; CHECK-NEXT: %res6 = add i32 %res1, 3
-; CHECK-NEXT: %res7 = add i32 5, %res4
-; CHECK-NEXT: %res = add i32 %res6, 5
-; CHECK-NEXT: ret i32 %res
+; CHECK-NEXT: %res5 = select i1 true, i32 5, i32 6
define internal i32 @f2(i32 %x) {
entry:
%cmp = icmp sgt i32 %x, 300
@@ -54,7 +57,8 @@ entry:
%call2 = tail call i32 @f1(i32 47, i32 999)
%call3 = tail call i32 @f2(i32 47)
%call4 = tail call i32 @f2(i32 301)
- %res.1 = add nsw i32 12, %call3
+ %res = add nsw i32 %call1, %call2
+ %res.1 = add nsw i32 %res, %call3
%res.2 = add nsw i32 %res.1, %call4
ret i32 %res.2
}
@@ -141,9 +145,9 @@ define double @test_struct({ double, dou
; Constant range for %x is [47, 302)
; CHECK-LABEL: @f5
; CHECK-NEXT: entry:
-; CHECK-NEXT: %cmp = icmp sgt i32 %x, undef
-; CHECK-NEXT: %res1 = select i1 %cmp, i32 1, i32 2
-; CHECK-NEXT: %res = add i32 %res1, 3
+; CHECK-NEXT: %res1 = select i1 undef, i32 1, i32 2
+; CHECK-NEXT: %res2 = select i1 undef, i32 3, i32 4
+; CHECK-NEXT: %res = add i32 %res1, %res2
; CHECK-NEXT: ret i32 %res
define internal i32 @f5(i32 %x) {
entry:
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