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2013-03-18Check whether a pointer is non-null (isKnownNonNull) in isKnownNonZero.Manman Ren
This handles the case where we have an inbounds GEP with alloca as the pointer. This fixes the regression in PR12750 and rdar://13286434. Note that we can also fix this by handling some GEP cases in isKnownNonNull. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177321 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-01Rewrite instsimplify's handling if icmp on pointer values to remove theDan Gohman
remaining use of AliasAnalysis concepts such as isIdentifiedObject to prove pointer inequality. @external_compare in test/Transforms/InstSimplify/compare.ll shows a simple case where a noalias argument can be equal to a global variable address, and while AliasAnalysis can get away with saying that these pointers don't alias, instsimplify cannot say that they are not equal. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174122 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-31An alloca can be equal to an argument. It can't *alias* an alloca, but it couldDan Gohman
be equal, since there's nothing preventing a caller from correctly predicting the stack location of an alloca. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174119 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-07Add support to ValueTracking for determining that a pointer is non-nullChandler Carruth
by virtue of inbounds GEPs that preclude a null pointer. This is a very common pattern in the code generated by std::vector and other standard library routines which use allocators that test for null pervasively. This is one step closer to teaching Clang+LLVM to be able to produce an empty function for: void f() { std::vector<int> v; v.push_back(1); v.push_back(2); v.push_back(3); v.push_back(4); } Which is related to getting them to completely fold SmallVector push_back sequences into constants when inlining and other optimizations make that a possibility. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169573 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-16InstructionSimplify should be able to simplify A+B==B+A to 'true'Duncan Sands
but wasn't due to the same logic bug that caused PR14361. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168186 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-25Teach instsimplify how to simplify comparisons of pointers which areChandler Carruth
constant-offsets of a common base using the generic GEP-walking logic I added for computing pointer differences in the same situation. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153419 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-26Reinstate the optimization from r151449 with a fix to not turn 'gep %x' intoNick Lewycky
'gep null' when the icmp predicate is unsigned (or is signed without inbounds). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151467 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-25Roll these back to r151448 until I figure out how they're breakingNick Lewycky
MultiSource/Applications/lua. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151463 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-25An argument and a local identified object (eg. a noalias call) could turn outNick Lewycky
equal if both are null. In the test, scope type %t and global @y by adding a 'gep' prefix to them. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151452 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-25Teach instsimplify to be more aggressive when analyzing comparisons of pointersNick Lewycky
by using llvm::isIdentifiedObject. Also teach it to handle GEPs that have the same base pointer and constant operands. Fixes PR11238! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151449 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-24fix PR12075, a regression in a recent transform I added. In unreachable ↵Chris Lattner
code, gep chains can be infinite. Just like "stripPointerCasts", use a set to keep track of visited instructions so we don't recurse infinitely. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151383 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-20fold comparisons of gep'd alloca points with null to false,Chris Lattner
implementing PR12013. We now compile the testcase to: __Z4testv: ## @_Z4testv ## BB#0: ## %_ZN4llvm15SmallVectorImplIiE9push_backERKi.exit pushq %rbx subq $64, %rsp leaq 32(%rsp), %rbx movq %rbx, (%rsp) leaq 64(%rsp), %rax movq %rax, 16(%rsp) movl $1, 32(%rsp) leaq 36(%rsp), %rax movq %rax, 8(%rsp) leaq (%rsp), %rdi callq __Z1gRN4llvm11SmallVectorIiLj8EEE movq (%rsp), %rdi cmpq %rbx, %rdi je LBB0_2 ## BB#1: callq _free LBB0_2: ## %_ZN4llvm11SmallVectorIiLj8EED1Ev.exit addq $64, %rsp popq %rbx ret instead of: __Z4testv: ## @_Z4testv ## BB#0: pushq %rbx subq $64, %rsp xorl %eax, %eax leaq (%rsp), %rbx addq $32, %rbx movq %rbx, (%rsp) movq %rbx, 8(%rsp) leaq 64(%rsp), %rcx movq %rcx, 16(%rsp) je LBB0_2 ## BB#1: movl $1, 32(%rsp) movq %rbx, %rax LBB0_2: ## %_ZN4llvm15SmallVectorImplIiE9push_backERKi.exit addq $4, %rax movq %rax, 8(%rsp) leaq (%rsp), %rdi callq __Z1gRN4llvm11SmallVectorIiLj8EEE movq (%rsp), %rdi cmpq %rbx, %rdi je LBB0_4 ## BB#3: callq _free LBB0_4: ## %_ZN4llvm11SmallVectorIiLj8EED1Ev.exit addq $64, %rsp popq %rbx ret This doesn't shrink clang noticably though. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150944 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-18Fix a rather nasty regression from r150690: LHS != RHS does not imply ↵Eli Friedman
LHS->stripPointerCasts() != RHS->stripPointerCasts(). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150863 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-16InstSimplify: Ignore pointer casts when constant folding compares between ↵Benjamin Kramer
pointers. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150690 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-10Fix PR11948: the result type of an icmp may be a vector of boolean -Duncan Sands
don't assume it is a boolean. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150247 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-10Revert commit 149912 (lattner) and add a testcase that shows the problem (whichDuncan Sands
is that patterns no longer match for vectors of booleans, because you only get ConstantDataVector when the vector element type is i8, i16, etc, not when it is i1). Original commit message: Remove some dead code and tidy things up now that vectors use ConstantDataVector instead of always using ConstantVector. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150246 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-08Fix code to match comment. Fixes PR11340, a regression from r143209.Eli Friedman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144121 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-30Reapply commit 143214 with a fix: m_ICmp doesn't match conditionsDuncan Sands
with the given predicate, it matches any condition and returns the predicate - d'oh! Original commit message: The expression icmp eq (select (icmp eq x, 0), 1, x), 0 folds to false. Spotted by my super-optimizer in 186.crafty and 450.soplex. We really need a proper infrastructure for handling generalizations of this kind of thing (which occur a lot), however this case is so simple that I decided to go ahead and implement it directly. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143318 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-29Revert r143214; it's breaking a bunch of stuff.Eli Friedman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143265 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-28The expression icmp eq (select (icmp eq x, 0), 1, x), 0 folds to false.Duncan Sands
Spotted by my super-optimizer in 186.crafty and 450.soplex. We really need a proper infrastructure for handling generalizations of this kind of thing (which occur a lot), however this case is so simple that I decided to go ahead and implement it directly. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143214 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-28Fold icmp ugt (udiv X, Y), X to false. Spotted by my super-optimizerDuncan Sands
in 186.crafty. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143209 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-27Reapply commit 143028 with a fix: the problem was casting a ConstantExpr MulDuncan Sands
using BinaryOperator (which only works for instructions) when it should have been a cast to OverflowingBinaryOperator (which also works for constants). While there, correct a few other dubious looking uses of BinaryOperator. Thanks to Chad Rosier for the testcase. Original commit message: My super-optimizer noticed that we weren't folding this expression to true: (x *nsw x) sgt 0, where x = (y | 1). This occurs in 464.h264ref. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143125 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-27Revert Duncan's r143028 expression folding which appears to be the culpritBob Wilson
behind a compile failure on 483.xalancbmk. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143102 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-26My super-optimizer noticed that we weren't folding this expression toDuncan Sands
true: (x *nsw x) sgt 0, where x = (y | 1). This occurs in 464.h264ref. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143028 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-19Remove bogus test: for all possible inputs of %X, the 'sub nsw' is guaranteedNick Lewycky
to perform a signed wrap. Don't rely on any particular handling of that case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135471 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-12Teach ComputeMaskedBits about sub nsw.Benjamin Kramer
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127548 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-11Teach ComputeMaskedBits about nsw on add. I don't think there's anything we canNick Lewycky
do with nuw here, but sub and mul should be given similar treatment. Fixes PR9343 #15! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127463 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-09Fix mistyped CHECK lines.Benjamin Kramer
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127366 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-09Add another micro-optimization. Apologies for the lack of refactoring, but INick Lewycky
gave up when I realized I couldn't come up with a good name for what the refactored function would be, to describe what it does. This is PR9343 test12, which is test3 with arguments reordered. Whoops! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127318 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-05Thread comparisons over udiv/sdiv/ashr/lshr exact and lshr nuw/nsw wheneverNick Lewycky
possible. This goes into instcombine and instsimplify because instsimplify doesn't need to check hasOneUse since it returns (almost exclusively) constants. This fixes PR9343 #4 #5 and #8! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127064 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-04Revert broken srem logic from r126991.Nick Lewycky
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127021 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-04Fold "icmp pred (srem X, Y), Y" like we do for urem. Handle signed comparisonsNick Lewycky
in the urem case, though not the other way around. This is enough to get #3 from PR9343! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126991 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-04Teach instruction simplify to use constant ranges to solve problems of the formNick Lewycky
"icmp pred %X, CI" and a number of examples where "%X = binop %Y, CI2". Some of these cases (div and rem) used to make it through opt -O2, but the others are probably now making code elsewhere redundant (probably instcombine). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126988 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-01Optimize "icmp pred (urem X, Y), Y" --> true/false depending on pred. There'sNick Lewycky
more work to do here, "icmp ult (urem X, 10), 11" doesn't optimize away yet. Fixes example 3 from PR9343! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126741 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-13Teach instsimplify that X+Y>=X+Z is the same as Y>=Z if neither side overflows,Duncan Sands
plus some variations of this. According to my auto-simplifier this occurs a lot but usually in combination with max/min idioms. Because max/min aren't handled yet this unfortunately doesn't have much effect in the testsuite. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125462 91177308-0d34-0410-b5e6-96231b3b80d8
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