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path: root/lib/Analysis/ScalarEvolution.cpp
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2008-11-03Don't crash analyzing certain quadratics (addrec of {X,+,Y,+,1}).Nick Lewycky
We're still waiting on code that actually analyzes them properly. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58592 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-13Disallow the construction of SCEVs with could-not-compute operands. Catch CNCsNick Lewycky
returned by BinomialCoefficient and don't try to operate with them. This replaces the previous fix for PR2857. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57431 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-04Allow the construction of SCEVs with SCEVCouldNotCompute operands, byNick Lewycky
implementing folding. Fixes PR2857. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57049 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-16Finally re-apply r46959. This is made feasible by the combinationDan Gohman
of r56230, r56232, and r56246. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56247 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-16Improve instcombine's handling of integer min and max in two ways:Dan Gohman
- Recognize expressions like "x > -1 ? x : 0" as min/max and turn them into expressions like "x < 0 ? 0 : x", which is easily recognizable as a min/max operation. - Refrain from folding expression like "y/2 < 1" to "y < 2" when the comparison is being used as part of a min or max idiom, like "y/2 < 1 ? 1 : y/2". In that case, the division has another use, so folding doesn't eliminate it, and obfuscates the min/max, making it harder to recognize as a min/max operation. These benefit ScalarEvolution, CodeGen, and anything else that wants to recognize integer min and max. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56246 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-15Teach ScalarEvolution to consider loop preheaders in the search forDan Gohman
an if statement that guards a loop, to allow indvars to avoid smax operations in more situations. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56232 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-14Fix WriteAsOperand to not emit a leading space character. AdjustDan Gohman
its callers to emit a space character before calling it when a space is needed. This fixes several spurious whitespace issues in ScalarEvolution's debug dumps. See the test changes for examples. This also fixes odd space-after-tab indentation in the output for switch statements, and changes calls from being printed like this: call void @foo( i32 %x ) to this: call void @foo(i32 %x) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56196 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-12Extend ScalarEvolution's executesAtLeastOnce logic to be able toDan Gohman
continue past the first conditional branch when looking for a relevant test. This helps it avoid using MAX expressions in loop trip counts in more cases. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54697 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-08Canonicalize nested AddRecs in by nesting them in order of loop depth.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54545 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-04PR2621: Improvements to the SCEV AddRec binomial expansion. This Eli Friedman
version uses a new algorithm for evaluating the binomial coefficients which is significantly more efficient for AddRecs of more than 2 terms (see the comments in the code for details on how the algorithm works). It also fixes some bugs: it removes the arbitrary length restriction for AddRecs, it fixes the silent generation of incorrect code for AddRecs which require a wide calculation width, and it fixes an issue where we were incorrectly truncating the iteration count too far when evaluating an AddRec expression narrower than the induction variable. There are still a few related issues I know of: I think there's still an issue with the SCEVExpander expansion of AddRec in terms of the width of the induction variable used. The hack to avoid generating too-wide integers shouldn't be necessary; instead, the callers should be considering the cost of the expansion before expanding it (in addition to not expanding too-wide integers, we might not want to expand expressions that are really expensive, especially when optimizing for size; calculating an length-17 32-bit AddRec currently generates about 250 instructions of straight-line code on X86). Also, for long 32-bit AddRecs on X86, CodeGen really sucks at scheduling the code. I'm planning on filing follow-up PRs for these issues. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54332 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-30Another SCEV issue from PR2607; essentially the same issue, but this Eli Friedman
time applying to the implicit comparison in smin expressions. The correct way to transform an inequality into the opposite inequality, either signed or unsigned, is with a not expression. I looked through the SCEV code, and I don't think there are any more occurrences of this issue. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54194 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-30Fix for PR2607: SCEV miscomputing the loop count for loops with an Eli Friedman
SGT exit condition. Essentially, the correct way to flip an inequality in 2's complement is the not operator, not the negation operator. That said, the difference only affects cases involving INT_MIN. Also, enhance the pre-test search logic to be a bit smarter about inequalities flipped with a not operator, so it can eliminate the smax from the iteration count for simple loops. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54184 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-21Revert r53812 -- premature. LegalizeTypes isn't actually on yet!Nick Lewycky
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53816 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-21Switch on the use of arbitrary precision integers in scalar evolution. This willNick Lewycky
bail after 256-bits to avoid producing code that the backends can't handle. Previously, we capped it at 64-bits, preferring to miscompile in those cases. This change also reverts much of r52248 because the invariants the code was expecting are now being met. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53812 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-20This header isn't necessary now.Wojciech Matyjewicz
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53811 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-20Fix PR2088. Use modulo linear equation solver to compute loop iterationWojciech Matyjewicz
count. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53810 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-15Correct this inversion!Nick Lewycky
I swear that didn't show up in svn diff... git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53587 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-15Fix up comments.Nick Lewycky
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53586 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-12Stop creating extraneous smax/umax in SCEV. This removes a regression where weNick Lewycky
started complicating many loops ('for' loops, in fact). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53508 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-09Remove getValueRange from SCEV. It wasn't doing anything there anyways, and aNick Lewycky
more complete version is now available from the LoopVR pass. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53269 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-07Handle 'lshr' instruction with SCEVUDiv object.Nick Lewycky
Comment the xor %x, -1 case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53167 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-22Generalize createSCEV to be able to form SCEV expressions fromDan Gohman
ConstantExprs. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52615 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-18Move LSR's private isZero function to a public SCEV memberDan Gohman
function, and make use of it in several places. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52463 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-13Crash less. The i64 restriction in BinomialCoefficient caused some problemsNick Lewycky
with code that was expecting different bit widths for different values. Make getTruncateOrZeroExtend a method on ScalarEvolution, and use it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52248 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-25Don't treat values as signed when looking at loop steppings in HowForToNonZero.Nick Lewycky
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51560 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-13Clean up the use of static and anonymous namespaces. This turned upDan Gohman
several things that were neither in an anonymous namespace nor static but not intended to be global. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51017 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-06Fix typo and indentation.Nick Lewycky
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50706 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-20(re)fix handling of UGT. Pointed out by Nick Lewycky.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49991 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-20Switch to using Simplified ConstantFP::get API.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49977 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-18Fix a scalar evolution bug. Reversing everythingDale Johannesen
does not work because of 0; 2>0 but -2U is also >0. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49928 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-14In the special case, call the comparison function instead ofDan Gohman
manually performing the comparison. This allows the special case to work correctly even in the case where someone is experimenting with a different comparison function :-). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49670 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-20Restore isCFGOnly property of various analysis passes.Devang Patel
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48579 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-19PassInfo keep tracks whether a pass is an analysis pass or not.Devang Patel
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48554 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-25Temporarily reverting 46959.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47542 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-21Simplify this code, no functionality change.Nick Lewycky
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47434 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-21GlobalValues are Constants, remove redundant code. Also fix typo in a comment.Nick Lewycky
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47433 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-20Unbreak build with gcc 4.3: provide missed includes and silence most ↵Anton Korobeynikov
annoying warnings. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47367 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-20Use getConstant for ConstantInts.Nick Lewycky
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47361 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-20Add 'umax' similar to 'smax' SCEV. Closes PR2003.Nick Lewycky
Parse reversed smax and umax as smin and umin and express them with negative or binary-not SCEVs (which are really just subtract under the hood). Parse 'xor %x, -1' as (-1 - %x). Remove dead code (ConstantInt::get always returns a ConstantInt). Don't use getIntegerSCEV(-1, Ty). The first value is an int, then it gets passed into a uint64_t. Instead, create the -1 directly from ConstantInt::getAllOnesValue(). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47360 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-13Fix typo. Thanks to Duncan for noticing.Wojciech Matyjewicz
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47062 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-13Add comments as per review feedback.Wojciech Matyjewicz
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47061 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-12Fix PR2002. Suppose n is the initial value for the induction Wojciech Matyjewicz
variable (with step 1) and m is its final value. Then, the correct trip count is SMAX(m,n)-n. Previously, we used SMAX(0,m-n), but m-n may overflow and can't in general be interpreted as signed. Patch by Nick Lewycky. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47007 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-11If the LHS of the comparison is a loop-invariant we also want to move it Wojciech Matyjewicz
to the RHS. This simple change allows to compute loop iteration count for loops with condition similar to the one in the testcase (which seems to be quite common). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46959 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-11Fix PR1798 - an error in the evaluation of SCEVAddRecExpr at an Wojciech Matyjewicz
arbitrary iteration. The patch: 1) changes SCEVSDivExpr into SCEVUDivExpr, 2) replaces PartialFact() function with BinomialCoefficient(); the computations (essentially, the division) in BinomialCoefficient() are performed with the apprioprate bitwidth necessary to avoid overflow; unsigned division is used instead of the signed one. Computations in BinomialCoefficient() require support from the code generator for APInts. Currently, we use a hack rounding up the neccessary bitwidth to the nearest power of 2. The hack is easy to turn off in future. One remaining issue: we assume the divisor of the binomial coefficient formula can be computed accurately using 16 bits. It means we can handle AddRecs of length up to 9. In future, we should use APInts to evaluate the divisor. Thanks to Nicholas for cooperation! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46955 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-31Avoid unnecessarily casting away const, fixing a FIXME.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46591 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-02Don't be rude, emit debugging info where asked to.Nick Lewycky
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45485 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-29Remove attribution from file headers, per discussion on llvmdev.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45418 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-10Fix PR1850 by removing an unsafe transformation from VMCore/ConstantFold.cpp.Chris Lattner
Reimplement the xform in Analysis/ConstantFolding.cpp where we can use targetdata to validate that it is safe. While I'm in there, fix some const correctness issues and generalize the interface to the "operand folder". git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44817 91177308-0d34-0410-b5e6-96231b3b80d8
2007-11-25Add new SCEV, SCEVSMax. This allows LLVM to analyze do-while loops.Nick Lewycky
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44319 91177308-0d34-0410-b5e6-96231b3b80d8
2007-11-23simplify some code.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44295 91177308-0d34-0410-b5e6-96231b3b80d8
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