<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Tue, Mar 13, 2018 at 5:40 AM, Samuel Iglesias Gonsálvez <span dir="ltr"><<a href="mailto:siglesias@igalia.com" target="_blank">siglesias@igalia.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">OpSConvert interprets the MSB of the unsigned value as the sign bit and<br>
extends it to the new type. If we want to preserve the value, we need<br>
to use OpUConvert opcode.<br>
<br>
v2:<br>
- No need to check dst type.<br>
- Fix typo in comment.<br>
<br>
</span>v3:<br>
- Use src/dst bitsize to get the proper conversion opcode. (Jason)<br>
<span class=""><br>
Signed-off-by: Samuel Iglesias Gonsálvez <<a href="mailto:siglesias@igalia.com">siglesias@igalia.com</a>><br>
---<br>
</span> src/compiler/spirv/vtn_alu.c | 11 ++++++++++-<br>
1 file changed, 10 insertions(+), 1 deletion(-)<br>
<br>
diff --git a/src/compiler/spirv/vtn_alu.c b/src/compiler/spirv/vtn_alu.c<br>
index d0c9e316935..9dcd183a48d 100644<br>
--- a/src/compiler/spirv/vtn_alu.c<br>
+++ b/src/compiler/spirv/vtn_alu.c<br>
@@ -354,10 +354,19 @@ vtn_nir_alu_op_for_spirv_<wbr>opcode(struct vtn_builder *b,<br>
<span class=""> case SpvOpConvertFToS:<br>
case SpvOpConvertSToF:<br>
case SpvOpConvertUToF:<br></span></blockquote><div><br></div><div>We probably need to fix SToF and UToF as well.<br><br></div><div>I'm starting to wonder if we don't want to do them all at once. Maybe something like this:<br><br></div><div>nir_alu_type src_type;<br></div><div>switch (opcode) {<br></div><div>case SpvOpConvertFToS:<br></div><div>case SpvOpConvertFToU:<br></div><div>case SpvOpFConvert:<br></div><div> src_type = nir_type_float;<br></div><div> break;<br></div><div>case SpvOpConvertSToF:<br></div><div>case SpvOpSConvert:<br></div><div> src_type = nir_type_int;<br></div><div> break;<br></div><div>case SpvOpConvertUToF:<br></div><div>case SpvOpUConvert:<br></div><div> src_type = nir_type_uint;<br></div><div> break;<br></div><div>default:<br></div><div> unreachable("Invalid opcode");<br></div><div>}<br></div><div>src_type |= nir_alu_type_get_type_size(<wbr>src);<br><span class="gmail-"><br></span></div><div><div>nir_alu_type dst_type;<br></div><div>switch (opcode) {<br></div>...<br><div>default:<br></div><div> unreachable("Invalid opcode");<br></div><div>}<br></div><div>dst_type |= nir_alu_type_get_type_size(dst);<br><br></div><div>While we're at it, since types don't really matter (only bit sizes), maybe nir_alu_op_for_spirv_opcode should just take bit sizes instead of types. It would make things simpler and make it more obvious what data actually gets used.<br><br></div><div>Sorry I didn't notice the other conversion opcodes earlier. :-(<br></div><span class="gmail-"></span></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">
- case SpvOpSConvert:<br>
case SpvOpFConvert:<br>
return nir_type_conversion_op(src, dst, nir_rounding_mode_undef);<br>
<br>
+ case SpvOpSConvert: {<br>
</span>+ /* SPIR-V expects to interpret the unsigned value as signed and<br>
+ * sign extend. Return the opcode accordingly.<br>
+ */<br>
+ unsigned src_bit_size = nir_alu_type_get_type_size(<wbr>src);<br>
+ nir_alu_type src_type = nir_type_int | src_bit_size; <br></blockquote><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<span class="">+ unsigned dst_bit_size = nir_alu_type_get_type_size(<wbr>dst);<br>
</span>+ nir_alu_type dst_type = nir_type_int | dst_bit_size;<br>
+ return nir_type_conversion_op(src_<wbr>type, dst_type, nir_rounding_mode_undef);<br>
<div class="HOEnZb"><div class="h5">+ }<br>
/* Derivatives: */<br>
case SpvOpDPdx: return nir_op_fddx;<br>
case SpvOpDPdy: return nir_op_fddy;<br>
--<br>
2.14.1<br>
<br>
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