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Sanjay Patel f99d254aae [InstCombine] simplify min/max of min/max with same operands (PR35607)
This is the original integer variant requested in:
https://bugs.llvm.org/show_bug.cgi?id=35607

As noted in the TODO and several similar TODOs around this block,
we could do this in instsimplify, but then it would cost more
because we would be trying to match min/max via ValueTracking
in 2 different places.

There are 4 commuted variants for each of smin/smax/umin/umax
that are not matched here. There are also icmp predicate variants
that are not included in the affected test file because they are
already handled by instsimplify by folding the final icmp to
true/false.

https://rise4fun.com/Alive/3KVc

  Name: smax(smax, smin)
  %c1 = icmp slt i32 %x, %y
  %c2 = icmp slt i32 %y, %x
  %min = select i1 %c1, i32 %x, i32 %y
  %max = select i1 %c2, i32 %x, i32 %y
  %c3 = icmp sgt i32 %max, %min
  %r = select i1 %c3, i32 %max, i32 %min
  =>
  %r = %max

  Name: smin(smax, smin)
  %c1 = icmp slt i32 %x, %y
  %c2 = icmp slt i32 %y, %x
  %min = select i1 %c1, i32 %x, i32 %y
  %max = select i1 %c2, i32 %x, i32 %y
  %c3 = icmp sgt i32 %max, %min
  %r = select i1 %c3, i32 %min, i32 %max
  =>
  %r = %min

  Name: umax(umax, umin)
  %c1 = icmp ult i32 %x, %y
  %c2 = icmp ult i32 %y, %x
  %min = select i1 %c1, i32 %x, i32 %y
  %max = select i1 %c2, i32 %x, i32 %y
  %c3 = icmp ult i32 %min, %max
  %r = select i1 %c3, i32 %max, i32 %min
  =>
  %r = %max

  Name: umin(umax, umin)
  %c1 = icmp ult i32 %x, %y
  %c2 = icmp ult i32 %y, %x
  %min = select i1 %c1, i32 %x, i32 %y
  %max = select i1 %c2, i32 %x, i32 %y
  %c3 = icmp ult i32 %min, %max
  %r = select i1 %c3, i32 %min, i32 %max
  =>
  %r = %min

llvm-svn: 369386
2019-08-20 13:39:17 +00:00
clang [Syntax] Added function to get macro expansion tokens to TokenBuffer. 2019-08-20 13:34:01 +00:00
clang-tools-extra [clangd] Skip function bodies inside processed files while indexing 2019-08-20 08:54:30 +00:00
compiler-rt [compiler-rt][crt] Pass -fno-lto in check_cxx_section_exists 2019-08-20 07:41:14 +00:00
debuginfo-tests Make nrvo-string test more robust. 2019-06-27 20:38:37 +00:00
libclc Revert "Rename F_{None,Text,Append} to OF_{None,Text,Append}. NFC" 2019-08-05 17:23:23 +00:00
libcxx [libcxx] Fix build breakage on mips 2019-08-20 10:19:55 +00:00
libcxxabi Provide a meaningful diagnostic when LLVM_PATH doesn't point to a directory 2019-08-19 23:51:26 +00:00
libunwind [runtimes] Don't depend on libpthread on Android 2019-07-22 20:41:03 +00:00
lld [COFF] Require an explicit -implib option for creating implibs in mingw mode 2019-08-20 10:14:54 +00:00
lldb Fix build for r369374 2019-08-20 13:17:20 +00:00
llgo IR: Support parsing numeric block ids, and emit them in textual output. 2019-03-22 18:27:13 +00:00
llvm [InstCombine] simplify min/max of min/max with same operands (PR35607) 2019-08-20 13:39:17 +00:00
openmp [OpenMP] Enable warning about "implicit fallthrough" 2019-08-15 13:26:55 +00:00
parallel-libs Fix typos throughout the license files that somehow I and my reviewers 2019-01-21 09:52:34 +00:00
polly [Polly] Migrate llvm::make_unique to std::make_unique 2019-08-14 22:28:12 +00:00
pstl [pstl] Allow customizing whether per-TU insulation is provided 2019-08-13 12:49:00 +00:00
.arcconfig Update monorepo .arcconfig with new project callsign. 2019-01-31 14:34:59 +00:00
.clang-format Add .clang-tidy and .clang-format files to the toplevel of the 2019-01-29 16:43:16 +00:00
.clang-tidy Disable tidy checks with too many hits 2019-02-01 11:20:13 +00:00
.gitignore Change /build to /build* in top-level .gitignore. 2019-08-02 02:14:08 +00:00
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