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[ARM,MVE] Add intrinsics and isel for MVE integer VMLA.

Authored by simon_tatham on Mar 11 2020, 5:48 AM.

Description

[ARM,MVE] Add intrinsics and isel for MVE integer VMLA.

Summary:
These instructions compute multiply+add in integers, with one of the
operands being a splat of a scalar. (VMLA and VMLAS differ in whether
the splat operand is a multiplier or the addend.)

I've represented these in IR using existing standard IR operations for
the unpredicated forms. The predicated forms are done with target-
specific intrinsics, as usual.

When operating on n-bit vector lanes, only the bottom n bits of the
i32 scalar operand are used. So we have to tell that to isel lowering,
to allow it to remove a pointless sign- or zero-extension instruction
on that input register. That's done in PerformIntrinsicCombine, but
first I had to enable PerformIntrinsicCombine for MVE targets
(previously all the intrinsics it handled were for NEON), and make it
a method of ARMTargetLowering so that it can get at
SimplifyDemandedBits.

Reviewers: dmgreen, MarkMurrayARM, miyuki, ostannard

Reviewed By: dmgreen

Subscribers: kristof.beyls, hiraditya, danielkiss, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D76122

Details

Committed
simon_tathamMar 18 2020, 3:55 AM
Reviewer
dmgreen
Differential Revision
D76122: [ARM,MVE] Add intrinsics and isel for MVE integer VMLA.
Parents
rG8d019cda851a: Fix ac1d23ed7de01fb3 interaction with gold plugin
Branches
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