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Revision 3657cf5f363fd64aeaf06432e62e3960800927b0 authored by Andrew Adams on 26 January 2024, 17:26:12 UTC, committed by GitHub on 26 January 2024, 17:26:12 UTC 
Fix bounds_of_nested_lanes (#8039)
 
* Fix bounds_of_nested_lanes

bounds_of_nested_lanes assumed that one layer of nested vectorization
could be removed at a time. When faced with the expression:

min(ramp(x8(a), x8(b), 5), x40(27))

It panicked, because on the left hand side it reduced the bounds to
x8(a) ... x8(a) + x8(b) * 4, and on the right hand side it reduced the
bounds to 27. It then attempted to take a min of mismatched types.

In general we can't assume that binary operators on nested vectors have
the same nesting structure on both sides, so I just rewrote it to reduce
directly to a scalar.

Fixes #8038
1 parent 4590a09
Raw File
Simplify_Reinterpret.cpp 
#include "Simplify_Internal.h"

namespace Halide {
namespace Internal {

Expr Simplify::visit(const Reinterpret *op, ExprInfo *bounds) {
    Expr a = mutate(op->value, nullptr);

    int64_t ia;
    uint64_t ua;
    bool vector = op->type.is_vector() || a.type().is_vector();
    if (op->type == a.type()) {
        return a;
    } else if (const_int(a, &ia) && op->type.is_uint() && !vector) {
        // int -> uint
        return make_const(op->type, (uint64_t)ia);
    } else if (const_uint(a, &ua) && op->type.is_int() && !vector) {
        // uint -> int
        return make_const(op->type, (int64_t)ua);
    } else if (const Reinterpret *as_r = a.as<Reinterpret>()) {
        // Fold double-reinterprets.
        return mutate(reinterpret(op->type, as_r->value), bounds);
    } else if ((op->type.bits() == a.type().bits()) &&
               op->type.is_int_or_uint() &&
               a.type().is_int_or_uint()) {
        // Normalize to casts for non-lane-changing reinterprets.
        return cast(op->type, a);
    } else if (a.same_as(op->value)) {
        return op;
    } else {
        return reinterpret(op->type, a);
    }
}

}  // namespace Internal
}  // namespace Halide
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