Clang has the default FP contraction setting of “-ffp-contract=on”, which
doesn't really mean “on” in the conventional sense of the word, but rather
really means “according to the per-statement effective value of the relevant
pragma”.
Before this patch, Clang has that pragma defaulting to “off”. Since the
“-ffp-contract=on” mode is really an AND of two booleans and the second of them
defaults to “off”, the whole thing effectively defaults to “off”. This patch
changes the default value of the pragma to “on”, thus making the default pair of
booleans (on, on) rather than (on, off). This makes FP optimization slightly
more aggressive than before when not using either “-Ofast”, “-ffast-math”, or
“-ffp-contract=fast”. Even with this patch the compiler still respects
“-ffp-contract=off”.
As per a suggestion by Steve Canon, the added code does _not_ require “-O3” or
higher. This is so as to try our best to preserve identical floating-point
results for unchanged source code compiling for an unchanged target when only
changing from any optimization level in the set (“-O0”, “-O1”, “-O2”, “-O3”) to
any other optimization level in that set. “-Os” and “-Oz” seem to be behaving
identically, i.e. should probably be considered a part of the aforementioned
set, but I have not reviewed this rigorously. “-Ofast” is explicitly _not_ a
member of that set.
Patch authored by Abe Skolnik [a.skolnik@samsung.com] and Stephen Canon [scanon@apple.com].
Differential Revision: https://reviews.llvm.org/D24481
llvm-svn: 282259
r259537 added vfma/vfms to armv7, but the builtin was only lowered
on the AArch64 side. Instead of supporting it on ARM, get rid of it.
The vfms builtin lowered to:
%nb = fsub float -0.0, %b
%r = @llvm.fma.f32(%a, %nb, %c)
Instead, define the operation in terms of vfma, and swap the
multiplicands. It now lowers to:
%na = fsub float -0.0, %a
%r = @llvm.fma.f32(%na, %b, %c)
This matches the instruction more closely, and lets current LLVM
generate the "natural" operand ordering:
fmls.2s v0, v1, v2
instead of the crooked (but equivalent):
fmls.2s v0, v2, v1
Except for theses changes, assembly is identical.
LLVM accepts both commutations, and the LLVM tests in:
test/CodeGen/AArch64/arm64-fmadd.ll
test/CodeGen/AArch64/fp-dp3.ll
test/CodeGen/AArch64/neon-fma.ll
test/CodeGen/ARM/fusedMAC.ll
already check either the new one only, or both.
Also verified against the test-suite unittests.
llvm-svn: 266807
This is mostly a one-time autoconversion of tests that checked assembly after
"-Owhatever" compiles to only run "opt -mem2reg" and check the assembly. This
should make them much more stable to changes in LLVM so they won't break on
unrelated changes.
"opt -mem2reg" is a compromise designed to increase the readability of tests
that check dataflow, while minimizing dependency on LLVM. Hopefully mem2reg is
stable enough that no surpises will come along.
Should address http://llvm.org/PR26815.
llvm-svn: 263048
This reverts commit r253269.
This leads to assert / segfault triggering on the following reduced example:
float foo(float U, float base, float cell) { return (U = 2 * base) - cell; }
llvm-svn: 253337
In the final phase of the merge, I managed to disable a bunch of Clang
tests accidentally. Fortunately none of them seem to have broken in
the interim.
llvm-svn: 211149
A few (mostly CodeGen) parts of Clang were tightly coupled to the
AArch64 backend. Now that it's gone, they will not even compile.
I've also deduplicated RUN lines in many of the AArch64 tests. This
might improve "make check-all" time noticably: some of those NEON
tests were monsters.
llvm-svn: 209578
This adds Clang support for the ARM64 backend. There are definitely
still some rough edges, so please bring up any issues you see with
this patch.
As with the LLVM commit though, we think it'll be more useful for
merging with AArch64 from within the tree.
llvm-svn: 205100
Renato Golin