Commit Graph

4 Commits

Author SHA1 Message Date
Jatin Bhateja 3c29bacd43 [X86] Improvement in CodeGen instruction selection for LEAs (re-applying post required revision changes.)
Summary:
   1/  Operand folding during complex pattern matching for LEAs has been
       extended, such that it promotes Scale to accommodate similar operand
       appearing in the DAG.
       e.g.
         T1 = A + B
         T2 = T1 + 10
         T3 = T2 + A
       For above DAG rooted at T3, X86AddressMode will no look like
         Base = B , Index = A , Scale = 2 , Disp = 10

   2/  During OptimizeLEAPass down the pipeline factorization is now performed over LEAs
       so that if there is an opportunity then complex LEAs (having 3 operands)
       could be factored out.
       e.g.
         leal 1(%rax,%rcx,1), %rdx
         leal 1(%rax,%rcx,2), %rcx
       will be factored as following
         leal 1(%rax,%rcx,1), %rdx
         leal (%rdx,%rcx)   , %edx

   3/ Aggressive operand folding for AM based selection for LEAs is sensitive to loops,
      thus avoiding creation of any complex LEAs within a loop.

Reviewers: lsaba, RKSimon, craig.topper, qcolombet, jmolloy

Reviewed By: lsaba

Subscribers: jmolloy, spatel, igorb, llvm-commits

    Differential Revision: https://reviews.llvm.org/D35014

llvm-svn: 314886
2017-10-04 09:02:10 +00:00
Hans Wennborg 534bfbd3ba Revert r313343 "[X86] PR32755 : Improvement in CodeGen instruction selection for LEAs."
This caused PR34629: asserts firing when building Chromium. It also broke some
buildbots building test-suite as reported on the commit thread.

> Summary:
>    1/  Operand folding during complex pattern matching for LEAs has been
>        extended, such that it promotes Scale to accommodate similar operand
>        appearing in the DAG.
>        e.g.
>           T1 = A + B
>           T2 = T1 + 10
>           T3 = T2 + A
>        For above DAG rooted at T3, X86AddressMode will no look like
>           Base = B , Index = A , Scale = 2 , Disp = 10
>
>    2/  During OptimizeLEAPass down the pipeline factorization is now performed over LEAs
>        so that if there is an opportunity then complex LEAs (having 3 operands)
>        could be factored out.
>        e.g.
>           leal 1(%rax,%rcx,1), %rdx
>           leal 1(%rax,%rcx,2), %rcx
>        will be factored as following
>           leal 1(%rax,%rcx,1), %rdx
>           leal (%rdx,%rcx)   , %edx
>
>    3/ Aggressive operand folding for AM based selection for LEAs is sensitive to loops,
>       thus avoiding creation of any complex LEAs within a loop.
>
> Reviewers: lsaba, RKSimon, craig.topper, qcolombet
>
> Reviewed By: lsaba
>
> Subscribers: spatel, igorb, llvm-commits
>
> Differential Revision: https://reviews.llvm.org/D35014

llvm-svn: 313376
2017-09-15 18:40:26 +00:00
Jatin Bhateja 908c8b37c2 [X86] PR32755 : Improvement in CodeGen instruction selection for LEAs.
Summary:
   1/  Operand folding during complex pattern matching for LEAs has been
       extended, such that it promotes Scale to accommodate similar operand
       appearing in the DAG.
       e.g.
          T1 = A + B
          T2 = T1 + 10
          T3 = T2 + A
       For above DAG rooted at T3, X86AddressMode will no look like
          Base = B , Index = A , Scale = 2 , Disp = 10

   2/  During OptimizeLEAPass down the pipeline factorization is now performed over LEAs
       so that if there is an opportunity then complex LEAs (having 3 operands)
       could be factored out.
       e.g.
          leal 1(%rax,%rcx,1), %rdx
          leal 1(%rax,%rcx,2), %rcx
       will be factored as following
          leal 1(%rax,%rcx,1), %rdx
          leal (%rdx,%rcx)   , %edx

   3/ Aggressive operand folding for AM based selection for LEAs is sensitive to loops,
      thus avoiding creation of any complex LEAs within a loop.

Reviewers: lsaba, RKSimon, craig.topper, qcolombet

Reviewed By: lsaba

Subscribers: spatel, igorb, llvm-commits

Differential Revision: https://reviews.llvm.org/D35014

llvm-svn: 313343
2017-09-15 05:29:51 +00:00
Jatin Bhateja 1f41a505d6 [X86] Adding a test to demonstrate aggressive folding for LEA facotrization.
Differential Revision: https://reviews.llvm.org/D37257

llvm-svn: 311994
2017-08-29 10:49:33 +00:00