llvm-project/llvm
Florian Hahn d0208b4b1c Recommit r315288: [SCCP] Propagate integer range info for parameters in IPSCCP.
This version of the patch includes a fix addressing a stage2 LTO buildbot
failure and addressed some additional nits.

Original commit message:
This updates the SCCP solver to use of the ValueElement lattice for
parameters, which provides integer range information. The range
information is used to remove unneeded icmp instructions.

For the following function, f() can be optimized to ret i32 2 with
this change

    source_filename = "sccp.c"
    target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
    target triple = "x86_64-unknown-linux-gnu"

    ; Function Attrs: norecurse nounwind readnone uwtable
    define i32 @main() local_unnamed_addr #0 {
    entry:
      %call = tail call fastcc i32 @f(i32 1)
      %call1 = tail call fastcc i32 @f(i32 47)
      %add3 = add nsw i32 %call, %call1
      ret i32 %add3
    }

    ; Function Attrs: noinline norecurse nounwind readnone uwtable
    define internal fastcc i32 @f(i32 %x) unnamed_addr #1 {
    entry:
      %c1 = icmp sle i32 %x, 100

      %cmp = icmp sgt i32 %x, 300
      %. = select i1 %cmp, i32 1, i32 2
      ret i32 %.
    }

    attributes #1 = { noinline }

Reviewers: davide, sanjoy, efriedma, dberlin

Reviewed By: davide, dberlin

Subscribers: mcrosier, gberry, mssimpso, dberlin, llvm-commits

Differential Revision: https://reviews.llvm.org/D36656

llvm-svn: 316891
2017-10-30 10:07:42 +00:00
..
bindings Reverting r315590; it did not include changes for llvm-tblgen, which is causing link errors for several people. 2017-10-15 14:32:27 +00:00
cmake Force #define GTEST_LANG_CXX11. 2017-10-27 21:12:28 +00:00
docs [docs] Fix a small typo 2017-10-26 17:58:05 +00:00
examples Fix broken links to the Itanium CXX ABI 2017-09-12 00:19:11 +00:00
include [(new) Pass Manager] instantiate SimplifyCFG with the same options as the old PM 2017-10-29 20:49:31 +00:00
lib Recommit r315288: [SCCP] Propagate integer range info for parameters in IPSCCP. 2017-10-30 10:07:42 +00:00
projects
resources
runtimes
test Recommit r315288: [SCCP] Propagate integer range info for parameters in IPSCCP. 2017-10-30 10:07:42 +00:00
tools ELF: Add support for emitting dynamic relocations in the Android relocation packing format. 2017-10-27 17:49:40 +00:00
unittests Fix llvm-special-case-list-fuzzer regexp exception 2017-10-27 19:15:13 +00:00
utils Force #define GTEST_LANG_CXX11. 2017-10-27 21:12:28 +00:00
.arcconfig
.clang-format
.clang-tidy
.gitignore
CMakeLists.txt [CMake] Allow parent projects to use in-source builds 2017-10-19 00:43:48 +00:00
CODE_OWNERS.TXT Update my email addresses, NFC. 2017-10-26 10:16:54 +00:00
CREDITS.TXT Add myself to CREDITS.txt 2017-09-18 14:33:39 +00:00
LICENSE.TXT
LLVMBuild.txt
README.txt
RELEASE_TESTERS.TXT Update my email addresses, NFC. 2017-10-26 10:16:54 +00:00
configure
llvm.spec.in

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