This changes the default value used for mask policy from mask undisturbed to mask agnostic. In hardware, there may be a minor preference for ta/ma, but since this is only going to apply to instructions which don't use the mask policy bit, this is functionally mostly a nop. The main value is to make future changes to using MA when legal for masked instructions easier to review by reducing test churn.
The prior code was motivated by a desire to minimize state transitions between masked and unmasked code. This patch achieves the same effect using the demanded field logic (landed in afb45ff), and there are no regressions I spotted in the test diffs. (Given the size, I have only been able to skim.) I do want to call out that regressions are possible here; the demanded analysis only works on a block local scope right now, so e.g. a tight loop mixing masked and unmasked computation might see an extra vsetvli or two.
Differential Revision: https://reviews.llvm.org/D133803
One of the sources is the same size as the destination so that source
doesn't have an overlap with the destination register. By using the _TIED
form we avoid an early clobber contraint for that source.
This matches what was already done for instrinsics. ConvertToThreeAddress
will fix it if it can't stay tied.
Currently we allow half types in vectors if the scalar Zfh extension
is enabled. This behavior is not inline with the vector spec. For f32
and f64 types, the Zve32f, Zve64f, Zve64d, and V explicitly control
the availablity of floating point types in vectors.
In order to make our compiler compliant, we either need to remove all support
for half in vectors or we need an extension to control it.
Draft spec here https://github.com/riscv/riscv-v-spec/pull/780
Reviewed By: kito-cheng
Differential Revision: https://reviews.llvm.org/D121345
