Previously we emitted an fmadd and a fmadd+fneg and combined them with a shufflevector. But this doesn't follow the correct exception behavior for unselected elements so the backend can't merge them into the fmaddsub/fmsubadd instructions.
This patch restores the the fmaddsub intrinsics so we don't have two arithmetic operations. We lose out on optimization opportunity in the non-strict FP case, but I don't think this is a big loss. If someone gives us a test case we can look into adding instcombine/dagcombine improvements. I'd rather not have the frontend do completely different things for strict and non-strict.
This still has problems because target specific intrinsics don't support strict semantics yet. We also still have all of the problems with masking. But we at least generate the right instruction in constrained mode now.
Differential Revision: https://reviews.llvm.org/D74268
Shufflevector is easier to generate and matches what the backend pattern matches without relying on constant selects being turned into shuffles.
While I was there I also made the IR regular expressions a little stricter to ensure operand order on the shuffle.
llvm-svn: 336388
This patch replaces all packed (and scalar without rounding
mode) fused intrinsics with fmadd/fmaddsub variations.
Then fmadd/fmaddsub are lowered to native IR.
Patch by tkrupa
Reviewers: craig.topper, sroland, spatel, RKSimon
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D47444
llvm-svn: 333555
fma4 instructions zero the upper bits of the xmm register. fma3 instructions leave the bits unmodified. This requires separate builtins for the different semantics.
While we're cleaning up the scalar builtins this also removes the fma3 fmsub/fnmadd/fnmsub builtins by using negates in the header file.
llvm-svn: 318985
The backend should be able to combine the negates to create fmsub, fnmadd, and fnmsub. faddsub converting to fsubadd still needs work I think, but should be very doable.
This matches what we already do for the masked builtins.
This only covers the packed builtins. Scalar builtins will be done after FMA4 is fixed.
llvm-svn: 317873
The X86 clang/test/CodeGen/*builtins.c tests define the mm_malloc.h include
guard as a hack for avoiding its inclusion (mm_malloc.h requires a hosted
environment since it expects stdlib.h to be available - which is not the case
in these internal clang codegen tests).
This patch removes this hack and instead passes -ffreestanding to clang cc1.
Differential Revision: https://reviews.llvm.org/D24825
llvm-svn: 282581
Craig Topper