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path: root/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
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2011-01-28My auto-simplifier noticed that ((X/Y)*Y)/Y occurs several times in SPECDuncan Sands
benchmarks, and that it can be simplified to X/Y. (In general you can only simplify (Z*Y)/Y to Z if the multiplication did not overflow; if Z has the form "X/Y" then this is the case). This patch implements that transform and moves some Div logic out of instcombine and into InstructionSimplify. Unfortunately instcombine gets in the way somewhat, since it likes to change (X/Y)*Y into X-(X rem Y), so I had to teach instcombine about this too. Finally, thanks to the NSW/NUW flags, sometimes we know directly that "Z*Y" does not overflow, because the flag says so, so I added that logic too. This eliminates a bunch of divisions and subtractions in 447.dealII, and has good effects on some other benchmarks too. It seems to have quite an effect on tramp3d-v4 but it's hard to say if it's good or bad because inlining decisions changed, resulting in massive changes all over. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124487 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-22Add a generic expansion transform: A op (B op' C) -> (A op B) op' (A op C)Duncan Sands
if both A op B and A op C simplify. This fires fairly often but doesn't make that much difference. On gcc-as-one-file it removes two "and"s and turns one branch into a select. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122399 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-21Pull a few more simplifications out of instcombine (there are stillDuncan Sands
plenty left though!), in particular for multiplication. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122330 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-07PR5207: Change APInt methods trunc(), sext(), zext(), sextOrTrunc() andJay Foad
zextOrTrunc(), and APSInt methods extend(), extOrTrunc() and new method trunc(), to be const and to return a new value instead of modifying the object in place. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121120 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17InstCombine: Add a missing irem identity (X % X -> 0).Benjamin Kramer
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119538 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-13Generalize the reassociation transform in SimplifyCommutative (now renamed toDuncan Sands
SimplifyAssociativeOrCommutative) "(A op C1) op C2" -> "A op (C1 op C2)", which previously was only done if C1 and C2 were constants, to occur whenever "C1 op C2" simplifies (a la InstructionSimplify). Since the simplifying operand combination can no longer be assumed to be the right-hand terms, consider all of the possible permutations. When compiling "gcc as one big file", transform 2 (i.e. using right-hand operands) fires about 4000 times but it has to be said that most of the time the simplifying operands are both constants. Transforms 3, 4 and 5 each fired once. Transform 6, which is an existing transform that I didn't change, never fired. With this change, the testcase is now optimized perfectly with one run of instcombine (previously it required instcombine + reassociate + instcombine, and it may just have been luck that this worked). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119002 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-02Floating-point add, sub, and mul are now spelled fadd, fsub, and fmul,Dan Gohman
respectively. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97531 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-16There are two ways of checking for a given type, for example isa<PointerType>(T)Duncan Sands
and T->isPointerTy(). Convert most instances of the first form to the second form. Requested by Chris. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96344 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-15Uniformize the names of type predicates: rather than having isFloatTy andDuncan Sands
isInteger, we now have isFloatTy and isIntegerTy. Requested by Chris! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96223 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-17Fix comment.Owen Anderson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93679 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05Convert a ton of simple integer type equality tests to the new predicate.Benjamin Kramer
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92760 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05split mul/div/rem instructions out to their own file.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92689 91177308-0d34-0410-b5e6-96231b3b80d8