[llvm-commits] [llvm] r57049 - in /llvm/trunk: lib/Analysis/ScalarEvolution.cpp test/Transforms/IndVarsSimplify/2008-10-03-CouldNotCompute.ll
Nick Lewycky
nicholas at mxc.ca
Sat Oct 4 04:19:07 PDT 2008
Author: nicholas
Date: Sat Oct 4 06:19:07 2008
New Revision: 57049
URL: http://llvm.org/viewvc/llvm-project?rev=57049&view=rev
Log:
Allow the construction of SCEVs with SCEVCouldNotCompute operands, by
implementing folding. Fixes PR2857.
Added:
llvm/trunk/test/Transforms/IndVarsSimplify/2008-10-03-CouldNotCompute.ll
Modified:
llvm/trunk/lib/Analysis/ScalarEvolution.cpp
Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=57049&r1=57048&r2=57049&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Sat Oct 4 06:19:07 2008
@@ -676,6 +676,9 @@
return getAddRecExpr(Operands, AddRec->getLoop());
}
+ if (isa<SCEVCouldNotCompute>(Op))
+ return new SCEVCouldNotCompute();
+
SCEVTruncateExpr *&Result = (*SCEVTruncates)[std::make_pair(Op, Ty)];
if (Result == 0) Result = new SCEVTruncateExpr(Op, Ty);
return Result;
@@ -691,6 +694,9 @@
// operands (often constants). This would allow analysis of something like
// this: for (unsigned char X = 0; X < 100; ++X) { int Y = X; }
+ if (isa<SCEVCouldNotCompute>(Op))
+ return new SCEVCouldNotCompute();
+
SCEVZeroExtendExpr *&Result = (*SCEVZeroExtends)[std::make_pair(Op, Ty)];
if (Result == 0) Result = new SCEVZeroExtendExpr(Op, Ty);
return Result;
@@ -706,6 +712,9 @@
// operands (often constants). This would allow analysis of something like
// this: for (signed char X = 0; X < 100; ++X) { int Y = X; }
+ if (isa<SCEVCouldNotCompute>(Op))
+ return new SCEVCouldNotCompute();
+
SCEVSignExtendExpr *&Result = (*SCEVSignExtends)[std::make_pair(Op, Ty)];
if (Result == 0) Result = new SCEVSignExtendExpr(Op, Ty);
return Result;
@@ -734,6 +743,10 @@
// Sort by complexity, this groups all similar expression types together.
GroupByComplexity(Ops);
+ // Could not compute plus anything equals could not compute.
+ if (isa<SCEVCouldNotCompute>(Ops.back()))
+ return new SCEVCouldNotCompute();
+
// If there are any constants, fold them together.
unsigned Idx = 0;
if (SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
@@ -959,6 +972,21 @@
// Sort by complexity, this groups all similar expression types together.
GroupByComplexity(Ops);
+ if (isa<SCEVCouldNotCompute>(Ops.back())) {
+ // CNC * 0 = 0
+ for (unsigned i = 0, e = Ops.size() - 1; i != e; ++i) {
+ if (Ops[i]->getSCEVType() != scConstant)
+ break;
+
+ SCEVConstant *SC = cast<SCEVConstant>(Ops[i]);
+ if (SC->getValue()->isMinValue(false))
+ return SC;
+ }
+
+ // Otherwise, we can't compute it.
+ return new SCEVCouldNotCompute();
+ }
+
// If there are any constants, fold them together.
unsigned Idx = 0;
if (SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
@@ -1124,6 +1152,9 @@
// FIXME: implement folding of (X*4)/4 when we know X*4 doesn't overflow.
+ if (isa<SCEVCouldNotCompute>(LHS) || isa<SCEVCouldNotCompute>(RHS))
+ return new SCEVCouldNotCompute();
+
SCEVUDivExpr *&Result = (*SCEVUDivs)[std::make_pair(LHS, RHS)];
if (Result == 0) Result = new SCEVUDivExpr(LHS, RHS);
return Result;
@@ -1171,6 +1202,12 @@
}
}
+ // Refuse to build an AddRec out of SCEVCouldNotCompute.
+ for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
+ if (isa<SCEVCouldNotCompute>(Operands[i]))
+ return new SCEVCouldNotCompute();
+ }
+
SCEVAddRecExpr *&Result =
(*SCEVAddRecExprs)[std::make_pair(L, std::vector<SCEV*>(Operands.begin(),
Operands.end()))];
@@ -1193,6 +1230,21 @@
// Sort by complexity, this groups all similar expression types together.
GroupByComplexity(Ops);
+ if (isa<SCEVCouldNotCompute>(Ops.back())) {
+ // CNC smax +inf = +inf.
+ for (unsigned i = 0, e = Ops.size() - 1; i != e; ++i) {
+ if (Ops[i]->getSCEVType() != scConstant)
+ break;
+
+ SCEVConstant *SC = cast<SCEVConstant>(Ops[i]);
+ if (SC->getValue()->isMaxValue(true))
+ return SC;
+ }
+
+ // Otherwise, we can't compute it.
+ return new SCEVCouldNotCompute();
+ }
+
// If there are any constants, fold them together.
unsigned Idx = 0;
if (SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
@@ -1273,6 +1325,21 @@
// Sort by complexity, this groups all similar expression types together.
GroupByComplexity(Ops);
+ if (isa<SCEVCouldNotCompute>(Ops[0])) {
+ // CNC umax inf = inf.
+ for (unsigned i = 0, e = Ops.size() - 1; i != e; ++i) {
+ if (Ops[i]->getSCEVType() != scConstant)
+ break;
+
+ SCEVConstant *SC = cast<SCEVConstant>(Ops[i]);
+ if (SC->getValue()->isMaxValue(false))
+ return SC;
+ }
+
+ // Otherwise, we can't compute it.
+ return new SCEVCouldNotCompute();
+ }
+
// If there are any constants, fold them together.
unsigned Idx = 0;
if (SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
Added: llvm/trunk/test/Transforms/IndVarsSimplify/2008-10-03-CouldNotCompute.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IndVarsSimplify/2008-10-03-CouldNotCompute.ll?rev=57049&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/IndVarsSimplify/2008-10-03-CouldNotCompute.ll (added)
+++ llvm/trunk/test/Transforms/IndVarsSimplify/2008-10-03-CouldNotCompute.ll Sat Oct 4 06:19:07 2008
@@ -0,0 +1,32 @@
+; RUN: llvm-as < %s | opt -indvars
+; PR2857
+
+ at foo = external global i32 ; <i32*> [#uses=1]
+
+define void @test(i32 %n, i32 %arg) {
+entry:
+ br i1 false, label %bb.nph, label %return
+
+bb.nph: ; preds = %entry
+ %0 = load i32* @foo, align 4 ; <i32> [#uses=1]
+ %1 = sext i32 %0 to i64 ; <i64> [#uses=1]
+ br label %bb
+
+bb: ; preds = %bb, %bb.nph
+ %.in = phi i32 [ %2, %bb ], [ %n, %bb.nph ] ; <i32> [#uses=1]
+ %val.02 = phi i64 [ %5, %bb ], [ 0, %bb.nph ] ; <i64> [#uses=2]
+ %result.01 = phi i64 [ %4, %bb ], [ 0, %bb.nph ] ; <i64> [#uses=1]
+ %2 = add i32 %.in, -1 ; <i32> [#uses=2]
+ %3 = mul i64 %1, %val.02 ; <i64> [#uses=1]
+ %4 = add i64 %3, %result.01 ; <i64> [#uses=2]
+ %5 = add i64 %val.02, 1 ; <i64> [#uses=1]
+ %6 = icmp sgt i32 %2, 0 ; <i1> [#uses=1]
+ br i1 %6, label %bb, label %bb3.bb4_crit_edge
+
+bb3.bb4_crit_edge: ; preds = %bb
+ %.lcssa = phi i64 [ %4, %bb ] ; <i64> [#uses=0]
+ ret void
+
+return: ; preds = %entry
+ ret void
+}
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