Allow unsigned comparisons
With this patch we will optimistically assume that the result of an unsigned
comparison is the same as the result of the same comparison interpreted as
signed.
llvm-svn: 267559
diff --git a/polly/lib/Analysis/ScopDetection.cpp b/polly/lib/Analysis/ScopDetection.cpp
index 2e1caf5..4ee92fc 100644
--- a/polly/lib/Analysis/ScopDetection.cpp
+++ b/polly/lib/Analysis/ScopDetection.cpp
@@ -149,11 +149,6 @@
cl::Hidden, cl::init(false), cl::ZeroOrMore,
cl::cat(PollyCategory));
-static cl::opt<bool> AllowUnsigned("polly-allow-unsigned",
- cl::desc("Allow unsigned expressions"),
- cl::Hidden, cl::init(false), cl::ZeroOrMore,
- cl::cat(PollyCategory));
-
static cl::opt<bool, true>
TrackFailures("polly-detect-track-failures",
cl::desc("Track failure strings in detecting scop regions"),
@@ -385,13 +380,6 @@
}
ICmpInst *ICmp = cast<ICmpInst>(Condition);
- // Unsigned comparisons are not allowed. They trigger overflow problems
- // in the code generation.
- //
- // TODO: This is not sufficient and just hides bugs. However it does pretty
- // well.
- if (ICmp->isUnsigned() && !AllowUnsigned)
- return invalid<ReportUnsignedCond>(Context, /*Assert=*/true, BI, &BB);
// Are both operands of the ICmp affine?
if (isa<UndefValue>(ICmp->getOperand(0)) ||
diff --git a/polly/lib/Analysis/ScopDetectionDiagnostic.cpp b/polly/lib/Analysis/ScopDetectionDiagnostic.cpp
index 5d5a1a4..25b121b 100644
--- a/polly/lib/Analysis/ScopDetectionDiagnostic.cpp
+++ b/polly/lib/Analysis/ScopDetectionDiagnostic.cpp
@@ -196,22 +196,6 @@
}
//===----------------------------------------------------------------------===//
-// ReportUnsignedCond.
-
-std::string ReportUnsignedCond::getMessage() const {
- return ("Condition in BB '" + BB->getName()).str() +
- "' performs a comparision on (not yet supported) unsigned integers.";
-}
-
-std::string ReportUnsignedCond::getEndUserMessage() const {
- return "Unsupported comparision on unsigned integers encountered";
-}
-
-bool ReportUnsignedCond::classof(const RejectReason *RR) {
- return RR->getKind() == rrkUnsignedCond;
-}
-
-//===----------------------------------------------------------------------===//
// ReportUndefOperand.
std::string ReportUndefOperand::getMessage() const {
diff --git a/polly/lib/Analysis/ScopInfo.cpp b/polly/lib/Analysis/ScopInfo.cpp
index 3b8770a..0149196 100644
--- a/polly/lib/Analysis/ScopInfo.cpp
+++ b/polly/lib/Analysis/ScopInfo.cpp
@@ -1317,6 +1317,18 @@
isl_pw_aff *LHS, *RHS;
LHS = Stmt.getPwAff(SE.getSCEVAtScope(ICond->getOperand(0), L));
RHS = Stmt.getPwAff(SE.getSCEVAtScope(ICond->getOperand(1), L));
+
+ if (ICond->isUnsigned()) {
+ // For unsigned comparisons we assumed the signed bit of neither operand
+ // to be set. The comparison is equal to a signed comparison under this
+ // assumption.
+ auto *BB = Stmt.getEntryBlock();
+ S.recordAssumption(UNSIGNED, isl_pw_aff_nonneg_set(isl_pw_aff_copy(LHS)),
+ TI->getDebugLoc(), AS_ASSUMPTION, BB);
+ S.recordAssumption(UNSIGNED, isl_pw_aff_nonneg_set(isl_pw_aff_copy(RHS)),
+ TI->getDebugLoc(), AS_ASSUMPTION, BB);
+ }
+
ConsequenceCondSet =
buildConditionSet(ICond->getPredicate(), LHS, RHS, Domain);
}