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path: root/lib/Transforms/InstCombine/InstCombineCasts.cpp
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2010-01-11reenable the piece that turns trunc(zext(x)) -> x even if zext has multiple ↵Chris Lattner
uses, codegen has no apparent problem with the trunc version of this, because it turns into a simple subreg idiom git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93202 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-11Disable folding sext(trunc(x)) -> x (and other similar cast/cast cases) when ↵Chris Lattner
the trunc has multiple uses. Codegen is not able to coalesce the subreg case correctly and so this leads to higher register pressure and spilling (see PR5997). This speeds up 256.bzip2 from 8.60 -> 8.04s on my machine, ~7%. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93200 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-11Extend CanEvaluateZExtd to handle and/or/xor more aggressively in theChris Lattner
BitsToClear case. This allows it to promote expressions which have an and/or/xor after the lshr, promoting cases like test2 (from PR4216) and test3 (random extample extracted from a spec benchmark). clang now compiles the code in PR4216 into: _test_bitfield: ## @test_bitfield movl %edi, %eax orl $194, %eax movl $4294902010, %ecx andq %rax, %rcx orl $32768, %edi andq $39936, %rdi movq %rdi, %rax orq %rcx, %rax ret instead of: _test_bitfield: ## @test_bitfield movl %edi, %eax orl $194, %eax movl $4294902010, %ecx andq %rax, %rcx shrl $8, %edi orl $128, %edi shlq $8, %rdi andq $39936, %rdi movq %rdi, %rax orq %rcx, %rax ret which is still not great, but is progress. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93145 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-11Remove the dead TD argument to CanEvaluateZExtd, and add aChris Lattner
new BitsToClear result which allows us to start promoting expressions that end with a lshr-by-constant. This is conservatively correct and better than what we had before (see testcases) but still needs to be extended further. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93144 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-11improve comments, remove dead TD argument to CanEvaluateSExtd.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93143 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-10teach sext optimization to handle truncs from types that are notChris Lattner
the dest of the sext. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93128 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-10teach zext optimization how to deal with truncs that don't come fromChris Lattner
the zext dest type. This allows us to handle test52/53 in cast.ll, and allows llvm-gcc to generate much better code for PR4216 in -m64 mode: _test_bitfield: ## @test_bitfield orl $32962, %edi movl %edi, %eax andl $-25350, %eax ret This also fixes a bug handling vector extends, ensuring that the mask produced is a vector constant, not an integer constant. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93127 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-10simplify CanEvaluateSExtd to return a bool now that we have aChris Lattner
simpler profitability predicate. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93111 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-10the NumCastsRemoved argument to CanEvaluateSExtd is dead, remove it.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93110 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-10now that the cost model has changed, we can always consider Chris Lattner
elimination of a sign extend to be a win, which simplifies the client of CanEvaluateSExtd, and allows us to eliminate more casts (examples taken from real code). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93109 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-10change the preferred canonical form for a sign extension to beChris Lattner
lshr+ashr instead of trunc+sext. We want to avoid type conversions whenever possible, it is easier to codegen expressions without truncates and extensions. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93107 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-10fix pasto that broke bootstrap.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93105 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-10simplify CanEvaluateZExtd now that we don't care about the number of Chris Lattner
bits known clear in the result and don't care about the # casts eliminated. TD is also dead but keeping it for now. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93098 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-10two changes: Chris Lattner
1) don't try to optimize a sext or zext that is only used by a trunc, let the trunc get optimized first. This avoids some pointless effort in some common cases since instcombine scans down a block in the first pass. 2) Change the cost model for zext elimination to consider an 'and' cheaper than a zext. This allows us to do it more aggressively, and for the next patch to simplify the code quite a bit. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93097 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-10enhance CanEvaluateZExtd to handle shift left and sext, allowingChris Lattner
more expressions to be promoted and casts eliminated. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93096 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-10remove an xform subsumed by EvaluateInDifferentType.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93095 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-10clean up this xform by using m_Trunc.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93092 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-10inline and remove the rest of commonIntCastTransforms.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93091 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-10Inline the expression type promotion/demotion stuff out ofChris Lattner
commonIntCastTransforms into the callers, eliminating a switch, and allowing the static predicate methods to be moved down to live next to the corresponding function. No functionality change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93089 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-08mplement a theoretical fixme.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93024 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-08rename CanEvaluateInDifferentType -> CanEvaluateTruncated and Chris Lattner
simplify it now that it is only used for truncates. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93021 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-07Enhance instcombine to reason more strongly about promoting computationChris Lattner
that feeds into a zext, similar to the patch I did yesterday for sext. There is a lot of room for extension beyond this patch. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92962 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-06tweaks suggested by DuncanChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92824 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-06Teach instcombine's sext elimination logic to be more aggressive.Chris Lattner
Previously, instcombine would only promote an expression tree to the larger type if doing so eliminated two casts. This is because a need to manually do the sign extend after the promoted expression tree with two shifts. Now, we keep track of whether the result of the computation is going to be properly sign extended already. If so, we can unconditionally promote the expression, which allows us to zap more sext's. This implements rdar://6598839 (aka gcc pr38751) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92815 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05simplify this code.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92800 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05make this a static function instead of a method.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92795 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05more rearrangement and cleanup, fix my test failure.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92792 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05cleanupChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92790 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05remove two trunc xforms that are subsumed by EvaluateInDifferentType.Chris Lattner
The only difference is that EvaluateInDifferentType checks to ensure they are profitable before doing them :) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92788 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05just remove this xform which is subsumed by others.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92775 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05move a trunc-specific transform out of commonIntCastTransforms into visitTrunc.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92773 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05move a zext specific xform out of commonIntCastTransforms into visitZExt and ↵Chris Lattner
modernize it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92770 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05move a trunc-specific xform out of commonIntCastTransforms into visitTruncChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92768 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
2010-01-05Avoid going through the LLVMContext for type equality where it's safe to ↵Benjamin Kramer
dereference the type pointer. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92726 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-04move some more cast-related stuffChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92471 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-04move the [Can]EvaluateInDifferentType functions out to InstCombineCasts.cppChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92469 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-04split 943 lines of instcombine out to a new InstCombineCasts.cppChris Lattner
file. InstructionCombining.cpp is now down to a svelte 9300 lines :) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92468 91177308-0d34-0410-b5e6-96231b3b80d8
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