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path: root/llvm/lib/Transforms/Scalar/StraightLineStrengthReduce.cpp
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* [SLSR] S's basis must have the same type as SJingyue Wu2015-06-281-2/+4
| | | | llvm-svn: 240910
* [NFC] more comments in SLSRJingyue Wu2015-06-181-0/+9
| | | | llvm-svn: 239984
* SLSR: Pass address space to isLegalAddressingModeMatt Arsenault2015-06-111-1/+3
| | | | | | | | | This only updates one of the uses. The other is used in cases that may never touch memory, so I'm not sure why this is even calling it. Perhaps there should be a new, similar hook for such cases or pass -1 for unknown address space. llvm-svn: 239540
* [ScalarEvolution] refactor: extract interface getGEPExprJingyue Wu2015-05-181-15/+18
| | | | | | | | | | | | | | | | | | Summary: This allows other passes (such as SLSR) to compute the SCEV expression for an imaginary GEP. Test Plan: no regression Reviewers: atrick, sanjoy Reviewed By: sanjoy Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D9786 llvm-svn: 237589
* [SLSR] handle (B | i) * SJingyue Wu2015-05-151-3/+21
| | | | | | | | | | | | | | | | Summary: Consider (B | i) * S as (B + i) * S if B and i have no bits set in common. Test Plan: @or in slsr-mul.ll Reviewers: broune, meheff Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D9788 llvm-svn: 237456
* [SLSR] handles non-canonicalized Mul candidatesJingyue Wu2015-05-131-2/+2
| | | | | | | | such as (2 + B) * S. Tested by @non_canonicalized in slsr-mul.ll llvm-svn: 237216
* [SLSR] garbage-collect unused instructionsJingyue Wu2015-04-211-3/+13
| | | | | | | | | | | | | | | | | Summary: After we rewrite a candidate, the instructions used by the old form may become unused. This patch cleans up these unused instructions so that we needn't run DCE after SLSR. Test Plan: removed -dce in all the SLSR tests Reviewers: broune, meheff Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D9101 llvm-svn: 235410
* [SLSR] handle candidate form (B + i * S)Jingyue Wu2015-04-151-91/+222
| | | | | | | | | | | | | | | | | | | | | | | | | | Summary: With this patch, SLSR may rewrite S1: X = B + i * S S2: Y = B + i' * S to S2: Y = X + (i' - i) * S A secondary improvement: if (i' - i) is a power of 2, emit Y as X + (S << log(i' - i)). (S << log(i' -i)) is in a canonical form and thus more likely GVN'ed than (i' - i) * S. Test Plan: slsr-add.ll Reviewers: hfinkel, sanjoy, meheff, broune, eliben Reviewed By: eliben Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D8983 llvm-svn: 235019
* [SLSR] consider &B[S << i] as &B[(1 << i) * S]Jingyue Wu2015-04-061-2/+7
| | | | | | | | | | | | | | Summary: This reduces handling &B[(1 << i) * s] to handling &B[i * S]. Test Plan: slsr-gep.ll Reviewers: meheff Subscribers: sanjoy, llvm-commits Differential Revision: http://reviews.llvm.org/D8837 llvm-svn: 234180
* [opaque pointer type] More GEP IRBuilder API migrations...David Blaikie2015-04-031-2/+3
| | | | llvm-svn: 234058
* [opaque pointer type] More GEP API migrations in IRBuilder usesDavid Blaikie2015-04-031-2/+2
| | | | | | | | | | | | | The plan here is to push the API changes out from the common components (like Constant::getGetElementPtr and IRBuilder::CreateGEP related functions) and just update callers to either pass the type if it's obvious, or pass null. Do this with LoadInst as well and anything else that comes up, then to start porting specific uses to not pass null anymore - this may require some refactoring in each case. llvm-svn: 234042
* [SLSR] handles off bounds GEPsJingyue Wu2015-04-021-5/+12
| | | | | | | | | | | | | | | | | | Summary: The old requirement on GEP candidates being in bounds is unnecessary. For off-bound GEPs, we still have &B[i * S] = B + (i * S) * e = B + (i * e) * S Test Plan: slsr_offbound_gep in slsr-gep.ll Reviewers: meheff Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D8809 llvm-svn: 233949
* [SLSR] handle candidate form &B[i * S]Jingyue Wu2015-03-261-67/+328
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: This patch enhances SLSR to handle another candidate form &B[i * S]. If we found two candidates S1: X = &B[i * S] S2: Y = &B[i' * S] and S1 dominates S2, we can replace S2 with Y = &X[(i' - i) * S] Test Plan: slsr-gep.ll X86/no-slsr.ll: verify that we do not run SLSR on GEPs that already fit into an addressing mode Reviewers: eliben, atrick, meheff, hfinkel Reviewed By: hfinkel Subscribers: sanjoy, llvm-commits Differential Revision: http://reviews.llvm.org/D7459 llvm-svn: 233286
* Fixing a -Wsign-compare warning; NFCAaron Ballman2015-02-041-1/+1
| | | | llvm-svn: 228142
* Add straight-line strength reduction to LLVMJingyue Wu2015-02-031-0/+274
Summary: Straight-line strength reduction (SLSR) is implemented in GCC but not yet in LLVM. It has proven to effectively simplify statements derived from an unrolled loop, and can potentially benefit many other cases too. For example, LLVM unrolls #pragma unroll foo (int i = 0; i < 3; ++i) { sum += foo((b + i) * s); } into sum += foo(b * s); sum += foo((b + 1) * s); sum += foo((b + 2) * s); However, no optimizations yet reduce the internal redundancy of the three expressions: b * s (b + 1) * s (b + 2) * s With SLSR, LLVM can optimize these three expressions into: t1 = b * s t2 = t1 + s t3 = t2 + s This commit is only an initial step towards implementing a series of such optimizations. I will implement more (see TODO in the file commentary) in the near future. This optimization is enabled for the NVPTX backend for now. However, I am more than happy to push it to the standard optimization pipeline after more thorough performance tests. Test Plan: test/StraightLineStrengthReduce/slsr.ll Reviewers: eliben, HaoLiu, meheff, hfinkel, jholewinski, atrick Reviewed By: jholewinski, atrick Subscribers: karthikthecool, jholewinski, llvm-commits Differential Revision: http://reviews.llvm.org/D7310 llvm-svn: 228016
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