Commit Graph

3 Commits

Author SHA1 Message Date
Chandler Carruth 0251556d45 Make '-disable-llvm-optzns' an alias for '-disable-llvm-passes'.
Much to my surprise, '-disable-llvm-optzns' which I thought was the
magical flag I wanted to get at the raw LLVM IR coming out of Clang
deosn't do that. It still runs some passes over the IR. I don't want
that, I really want the *raw* IR coming out of Clang and I strongly
suspect everyone else using it is in the same camp.

There is actually a flag that does what I want that I didn't know about
called '-disable-llvm-passes'. I suspect many others don't know about it
either. It both does what I want and is much simpler.

This removes the confusing version and makes that spelling of the flag
an alias for '-disable-llvm-passes'. I've also moved everything in Clang
to use the 'passes' spelling as it seems both more accurate (*all* LLVM
passes are disabled, not just optimizations) and much easier to remember
and spell correctly.

This is part of simplifying how Clang drives LLVM to make it cleaner to
wire up to the new pass manager.

Differential Revision: https://reviews.llvm.org/D28047

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@290392 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-23 00:23:01 +00:00
Sanjay Patel 9ac9c59216 convert builtin_unpredictable on a switch into metadata for LLVM
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@247203 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-09 22:39:06 +00:00
Sanjay Patel a43b1f18fd add __builtin_unpredictable and convert to metadata
This patch depends on r246688 (D12341).

The goal is to make LLVM generate different code for these functions for a target that
has cheap branches (see PR23827 for more details):

int foo();

int normal(int x, int y, int z) {
   if (x != 0 && y != 0) return foo();
   return 1;
}

int crazy(int x, int y) {
   if (__builtin_unpredictable(x != 0 && y != 0)) return foo();
   return 1;
}

Differential Revision: http://reviews.llvm.org/D12458



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@246699 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-02 20:01:30 +00:00