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[runtime-unroll] Inline canSafelyUnrollMultiExitLoop [NFC] 

All of the interesting logic from this routine has been removed, inline the single check into the sole non-assert caller.  The assert use has little value with the restructured code and is simply dropped.
This commit is contained in:
Philip Reames 2021-11-15 11:38:06 -08:00
parent 0c501db7d3
commit 423da61835
1 changed files with 5 additions and 28 deletions
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33
llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
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@ -411,35 +411,11 @@ CloneLoopBlocks(Loop *L, Value *NewIter, const bool UseEpilogRemainder,
return NewLoop;
}
/// Returns true if we can safely unroll a multi-exit/exiting loop. OtherExits
/// is populated with all the loop exit blocks other than the LatchExit block.
static bool canSafelyUnrollMultiExitLoop(Loop *L, BasicBlock *LatchExit,
bool PreserveLCSSA,
bool UseEpilogRemainder) {
// We currently have some correctness constrains in unrolling a multi-exit
// loop. Check for these below.
// We rely on LCSSA form being preserved when the exit blocks are transformed.
// (Note that only an off-by-default mode of the old PM disables PreserveLCCA.)
if (!PreserveLCSSA)
return false;
// All constraints have been satisfied.
return true;
}
/// Returns true if we can profitably unroll the multi-exit loop L. Currently,
/// we return true only if UnrollRuntimeMultiExit is set to true.
static bool canProfitablyUnrollMultiExitLoop(
Loop *L, SmallVectorImpl<BasicBlock *> &OtherExits, BasicBlock *LatchExit,
bool PreserveLCSSA, bool UseEpilogRemainder) {
#if !defined(NDEBUG)
assert(canSafelyUnrollMultiExitLoop(L, LatchExit, PreserveLCSSA,
UseEpilogRemainder) &&
"Should be safe to unroll before checking profitability!");
#endif
bool UseEpilogRemainder) {
// Priority goes to UnrollRuntimeMultiExit if it's supplied.
if (UnrollRuntimeMultiExit.getNumOccurrences())
@ -638,12 +614,13 @@ bool llvm::UnrollRuntimeLoopRemainder(
// Support only single exit and exiting block unless multi-exit loop
// unrolling is enabled.
if (!L->getExitingBlock() || OtherExits.size()) {
if (!canSafelyUnrollMultiExitLoop(L, LatchExit, PreserveLCSSA,
UseEpilogRemainder))
// We rely on LCSSA form being preserved when the exit blocks are transformed.
// (Note that only an off-by-default mode of the old PM disables PreserveLCCA.)
if (!PreserveLCSSA)
return false;
if (!canProfitablyUnrollMultiExitLoop(L, OtherExits, LatchExit,
PreserveLCSSA, UseEpilogRemainder)) {
UseEpilogRemainder)) {
LLVM_DEBUG(
dbgs()
<< "Multiple exit/exiting blocks in loop and multi-exit unrolling not "