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path: root/lib/Transforms/Scalar/LoopStrengthReduce.cpp
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2009-04-16Use a SCEV expression cast instead of immediately inserting aDan Gohman
new instruction with SCEVExpander::InsertCastOfTo. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69290 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-16Expand GEPs in ScalarEvolution expressions. SCEV expressions can nowDan Gohman
have pointer types, though in contrast to C pointer types, SCEV addition is never implicitly scaled. This not only eliminates the need for special code like IndVars' EliminatePointerRecurrence and LSR's own GEP expansion code, it also does a better job because it lets the normal optimizations handle pointer expressions just like integer expressions. Also, since LLVM IR GEPs can't directly index into multi-dimensional VLAs, moving the GEP analysis out of client code and into the SCEV framework makes it easier for clients to handle multi-dimensional VLAs the same way as other arrays. Some existing regression tests show improved optimization. test/CodeGen/ARM/2007-03-13-InstrSched.ll in particular improved to the point where if-conversion started kicking in; I turned it off for this test to preserve the intent of the test. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69258 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-17LSR shouldn't ever try to hack on integer IV's larger than 64-bits. Right nowChris Lattner
it is not APInt clean, but even when it is it needs to be evaluated carefully to determine whether it is actually profitable. This fixes a crash on PR3806 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67134 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-09Don't record the increment instruction; just recompute it from the PhiDan Gohman
if needed. This simplifies the code a little, and is needed for an upcoming refactoring. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66479 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-09Fix a few more places where induction variable types were usedDan Gohman
where memory access types are needed. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66470 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-09Use ReplacedTy instead of recomputing the same value.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66469 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-09Use LoopInfo's getLoopLatch() instead of doing what it does manualy.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66467 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-09Don't use an induction variable type as a memory access type.Dan Gohman
Use VoidTy instead, to be properly conservative. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66463 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-09Factor out the code that determines the memory access typeDan Gohman
of an instruction into a helper function. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66460 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-09Move the sorting of the StrideOrder array earlier so that it doesn'tDan Gohman
have to be done twice. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66449 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-09Delete the isOnlyStride argument, which is unused.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66446 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-09Tidy some LSR debug output: announce the loop it's about to processDan Gohman
before it does any processing. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66443 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-04Fix this comment.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66065 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-04Add an assertion for a condition that's always true, and notDan Gohman
immediately obvious. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66062 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-24Rename ScalarEvolution's getIterationCount to getBackedgeTakenCount,Dan Gohman
to more accurately describe what it does. Expand its doxygen comment to describe what the backedge-taken count is and how it differs from the actual iteration count of the loop. Adjust names and comments in associated code accordingly. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65382 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-24Generalize the ChangeCompareStride code, in preparation forDan Gohman
handling non-constant strides. No functionality change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65363 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-22Properly parenthesize this expression, fixing a real bug in the newDan Gohman
-full-lsr code, as well as a GCC warning. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65288 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-22Only try to sink immediate when TLI is not null. It needs to check if ↵Evan Cheng
immediate would fit in target addressing field. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65268 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-21Teach LSR sink to sink the immediate portion of the common expression back ↵Evan Cheng
into uses if they fit in address modes of all the uses. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65215 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-20Fix strange logic in CollectIVUsers used to determine whether all uses areEvan Cheng
addresses, part 1. This fixes an obvious logic bug. Previously if the only in-loop use is a PHI, it would return AllUsesAreAddresses as true. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65178 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-20Simplify code and reduce indentation. No functionality change.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65167 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-20Fix 80-column violations.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65159 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-20It's not necessary to check if Base is null here.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65157 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-20Add a comment about how Imm can be used for loop-variant values.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65147 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-20Implement "superhero" strength reduction, or full strengthDan Gohman
reduction of address calculations down to basic pointer arithmetic. This is currently off by default, as it needs a few other features before it becomes generally useful. And even when enabled, full strength reduction is only performed when it doesn't increase register pressure, and when several other conditions are true. This also factors out a bunch of exisiting LSR code out of StrengthReduceStridedIVUsers into separate functions, and tidies up IV insertion. This actually decreases register pressure even in non-superhero mode. The change in iv-users-in-other-loops.ll is an example of this; there are two more adds because there are two fewer leas, and there is less spilling. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65108 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-19Use DEBUG() instead of passing *DOUT to WriteAsOperand,Dan Gohman
since the latter just passes a null reference when debugging is not enabled. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65060 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-19Make the debug output of LSR less cryptic and more informative.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65057 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-18Fix a typo in a comment.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64859 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-17Strengthen the "non-constant stride must dominate loop preheader" check.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64703 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-15Fix pr3571: If stride is a value defined by an instruction, make sure it ↵Evan Cheng
dominates the loop preheader. When IV users are strength reduced, the stride is inserted into the preheader. It could create a use before def situation. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64579 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-15ifdef out unneeded if statement.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64575 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-13Complete the sentance in this comment. I have reservationsDan Gohman
about the code it describes, but at least now the comment is right. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64465 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-13Fix the code that checked if a SCEVAddRecExpr Start contains anDan Gohman
addrec in a different loop to check the value being added to the accumulated Start value, not the Start value before it has the new value added to it. This prevents LSR from going crazy on the included testcase. Dale, please review. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64440 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-13Fix LSR's IV sorting function to explicitly sort by bitwidthDan Gohman
after sorting by stride value. This prevents it from missing IV reuse opportunities in a host-sensitive manner. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64415 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-09Fix PR 3471, and some cleanups.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64177 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-14Fix the time regression I introduced in 464.h264ref withDale Johannesen
my earlier patch to this file. The issue there was that all uses of an IV inside a loop are actually references to Base[IV*2], and there was one use outside that was the same but LSR didn't see the base or the scaling because it didn't recurse into uses outside the loop; thus, it used base+IV*scale mode inside the loop instead of pulling base out of the loop. This was extra bad because register pressure later forced both base and IV into memory. Doing that recursion, at least enough to figure out addressing modes, is a good idea in general; the change in AddUsersIfInteresting does this. However, there were side effects.... It is also possible for recursing outside the loop to introduce another IV where there was only 1 before (if the refs inside are not scaled and the ref outside is). I don't think this is a common case, but it's in the testsuite. It is right to be very aggressive about getting rid of such introduced IVs (CheckForIVReuse and the handling of nonzero RewriteFactor in StrengthReduceStridedIVUsers). In the testcase in question the new IV produced this way has both a nonconstant stride and a nonzero base, neither of which was handled before. And when inserting new code that feeds into a PHI, it's right to put such code at the original location rather than in the PHI's immediate predecessor(s) when the original location is outside the loop (a case that couldn't happen before) (RewriteInstructionToUseNewBase); better to avoid making multiple copies of it in this case. Also, the mechanism for keeping SCEV's corresponding to GEP's no longer works, as the GEP might change after its SCEV is remembered, invalidating the SCEV, and we might get a bad SCEV value when looking up the GEP again for a later loop. This also couldn't happen before, as we weren't recursing into GEP's outside the loop. Also, when we build an expression that involves a (possibly non-affine) IV from a different loop as well as an IV from the one we're interested in (containsAddRecFromDifferentLoop), don't recurse into that. We can't do much with it and will get in trouble if we try to create new non-affine IVs or something. More testcases are coming. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62212 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-12Rename getABITypeSize to getTypePaddedSize, asDuncan Sands
suggested by Chris. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62099 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-23Revert 61362 and 61402 until SPEC breakage is fixed.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61403 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-23This fixes the bug in 175.vpr. It doesn't fix theDale Johannesen
other SPEC breakage. I'll be reverting all recent changes shortly, this checking is mostly so this change doesn't get lost. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61402 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-23Fix the time regression I introduced in 464.h264ref withDale Johannesen
my last patch to this file. The issue there was that all uses of an IV inside a loop are actually references to Base[IV*2], and there was one use outside that was the same but LSR didn't see the base or the scaling because it didn't recurse into uses outside the loop; thus, it used base+IV*scale mode inside the loop instead of pulling base out of the loop. This was extra bad because register pressure later forced both base and IV into memory. Doing that recursion, at least enough to figure out addressing modes, is a good idea in general; the change in AddUsersIfInteresting does this. However, there were side effects.... It is also possible for recursing outside the loop to introduce another IV where there was only 1 before (if the refs inside are not scaled and the ref outside is). I don't think this is a common case, but it's in the testsuite. It is right to be very aggressive about getting rid of such introduced IVs (CheckForIVReuse and the handling of nonzero RewriteFactor in StrengthReduceStridedIVUsers). In the testcase in question the new IV produced this way has both a nonconstant stride and a nonzero base, neither of which was handled before. And when inserting new code that feeds into a PHI, it's right to put such code at the original location rather than in the PHI's immediate predecessor(s) when the original location is outside the loop (a case that couldn't happen before) (RewriteInstructionToUseNewBase); better to avoid making multiple copies of it in this case. Also, the mechanism for keeping SCEV's corresponding to GEP's no longer works, as the GEP might change after its SCEV is remembered, invalidating the SCEV, and we might get a bad SCEV value when looking up the GEP again for a later loop. This also couldn't happen before, as we weren't recursing into GEP's outside the loop. I owe some testcases for this, want to get it in for nightly runs. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61362 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-18Revert previous patch, appears to break bootstrap.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61181 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-18Fix the time regression I introduced in 464.h264ref withDale Johannesen
my last patch to this file. The issue there was that all uses of an IV inside a loop are actually references to Base[IV*2], and there was one use outside that was the same but LSR didn't see the base or the scaling because it didn't recurse into uses outside the loop; thus, it used base+IV*scale mode inside the loop instead of pulling base out of the loop. This was extra bad because register pressure later forced both base and IV into memory. Doing that recursion, at least enough to figure out addressing modes, is a good idea in general; the change in AddUsersIfInteresting does this. However, there were side effects.... It is also possible for recursing outside the loop to introduce another IV where there was only 1 before (if the refs inside are not scaled and the ref outside is). I don't think this is a common case, but it's in the testsuite. It is right to be very aggressive about getting rid of such introduced IVs (CheckForIVReuse and the handling of nonzero RewriteFactor in StrengthReduceStridedIVUsers). In the testcase in question the new IV produced this way has both a nonconstant stride and a nonzero base, neither of which was handled before. (This patch does not handle all the cases where this can happen.) And when inserting new code that feeds into a PHI, it's right to put such code at the original location rather than in the PHI's immediate predecessor(s) when the original location is outside the loop (a case that couldn't happen before) (RewriteInstructionToUseNewBase); better to avoid making multiple copies of it in this case. Everything above is exercised in CodeGen/X86/lsr-negative-stride.ll (and ifcvt4 in ARM which is the same IR). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61178 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-16Clarify that the scale factor from CheckForIVReuseDale Johannesen
can be negative. Keep track of whether all uses of an IV are outside the loop. Some cosmetics; no functional change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61109 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-09Fix a really subtle off-by-one bug that Duncan noticed with valgrindChris Lattner
on test/CodeGen/Generic/2007-06-06-CriticalEdgeLandingPad. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60739 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-05Make LoopStrengthReduce smarter about hoisting things out ofDale Johannesen
loops when they can be subsumed into addressing modes. Change X86 addressing mode check to realize that some PIC references need an extra register. (I believe this is correct for Linux, if not, I'm sure someone will tell me.) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60608 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-03Remove an unused field.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60508 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-03Fix a misspelled function name.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60506 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-03Fix a really wrong comment.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60494 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-02Minor rewrite per review feedback.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60442 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-02Make the code do what the comment says it does.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60431 91177308-0d34-0410-b5e6-96231b3b80d8
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