bjoernager/rust
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Auto merge of #112718 - oli-obk:SIMD-destructure_mir_const, r=cjgillot

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Make simd_shuffle_indices use valtrees

This removes the second-to-last user of the `destructure_mir_constant` query. So in a follow-up we can remove the query and just move the query provider function directly into pretty printing (which is the last user).

cc `@rust-lang/clippy` there's a small functional change, but I think it is correct?
This commit is contained in:
bors 2023-07-02 07:43:36 +00:00
commit 72b2101434
7 changed files with 106 additions and 58 deletions
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8
compiler/rustc_codegen_ssa/src/mir/block.rs
View file

@ -870,13 +870,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
// promotes any complex rvalues to constants.
if i == 2 && intrinsic.as_str().starts_with("simd_shuffle") {
if let mir::Operand::Constant(constant) = arg {
let c = self.eval_mir_constant(constant);
let (llval, ty) = self.simd_shuffle_indices(
&bx,
constant.span,
self.monomorphize(constant.ty()),
c,
);
let (llval, ty) = self.simd_shuffle_indices(&bx, constant);
return OperandRef {
val: Immediate(llval),
layout: bx.layout_of(ty),

50
compiler/rustc_codegen_ssa/src/mir/constant.rs
View file

@ -5,7 +5,6 @@ use rustc_middle::mir;
use rustc_middle::mir::interpret::{ConstValue, ErrorHandled};
use rustc_middle::ty::layout::HasTyCtxt;
use rustc_middle::ty::{self, Ty};
use rustc_span::source_map::Span;
use rustc_target::abi::Abi;
use super::FunctionCx;
@ -59,22 +58,40 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
})
}
/// This is a convenience helper for `simd_shuffle_indices`. It has the precondition
/// that the given `constant` is an `ConstantKind::Unevaluated` and must be convertible to
/// a `ValTree`. If you want a more general version of this, talk to `wg-const-eval` on zulip.
pub fn eval_unevaluated_mir_constant_to_valtree(
&self,
constant: &mir::Constant<'tcx>,
) -> Result<Option<ty::ValTree<'tcx>>, ErrorHandled> {
let uv = match constant.literal {
mir::ConstantKind::Unevaluated(uv, _) => uv.shrink(),
other => span_bug!(constant.span, "{other:#?}"),
};
let uv = self.monomorphize(uv);
self.cx.tcx().const_eval_resolve_for_typeck(
ty::ParamEnv::reveal_all(),
uv,
Some(constant.span),
)
}
/// process constant containing SIMD shuffle indices
pub fn simd_shuffle_indices(
&mut self,
bx: &Bx,
span: Span,
ty: Ty<'tcx>,
constant: Result<ConstValue<'tcx>, ErrorHandled>,
constant: &mir::Constant<'tcx>,
) -> (Bx::Value, Ty<'tcx>) {
constant
let ty = self.monomorphize(constant.ty());
let val = self
.eval_unevaluated_mir_constant_to_valtree(constant)
.ok()
.flatten()
.map(|val| {
let field_ty = ty.builtin_index().unwrap();
let c = mir::ConstantKind::from_value(val, ty);
let values: Vec<_> = bx
.tcx()
.destructure_mir_constant(ty::ParamEnv::reveal_all(), c)
.fields
let values: Vec<_> = val
.unwrap_branch()
.iter()
.map(|field| {
if let Some(prim) = field.try_to_scalar() {
@ -88,15 +105,14 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
}
})
.collect();
let llval = bx.const_struct(&values, false);
(llval, c.ty())
bx.const_struct(&values, false)
})
.unwrap_or_else(|_| {
bx.tcx().sess.emit_err(errors::ShuffleIndicesEvaluation { span });
.unwrap_or_else(|| {
bx.tcx().sess.emit_err(errors::ShuffleIndicesEvaluation { span: constant.span });
// We've errored, so we don't have to produce working code.
let ty = self.monomorphize(ty);
let llty = bx.backend_type(bx.layout_of(ty));
(bx.const_undef(llty), ty)
})
bx.const_undef(llty)
});
(val, ty)
}
}