Bug 316382

Summary:	Support for AMDs FMA4 instructions seem to be missing
Product:	[Developer tools] valgrind	Reporter:	ake.sandgren
Component:	vex	Assignee:	Julian Seward <jseward>
Status:	RESOLVED DUPLICATE
Severity:	wishlist	CC:	mark, tom
Priority:	NOR
Version:	3.8.0
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed In:
Attachments:	Test case which reproduces illegal instruction (does not work with current trunk as well) Result of compilation

Description ake.sandgren 2013-03-08 19:14:46 UTC

I'm getting the following using valgrind 3.8.1
vex amd64->IR: unhandled instruction bytes: 0xC4 0x43 0x19 0x6B 0xE5 0xE0 0xF2 0
x44
vex amd64->IR:   REX=0 REX.W=0 REX.R=1 REX.X=0 REX.B=1
vex amd64->IR:   VEX=1 VEX.L=0 VEX.nVVVV=0xC ESC=0F3A
vex amd64->IR:   PFX.66=1 PFX.F2=0 PFX.F3=0

That comes from a vfmaddsd %xmm12,%xmm13,%xmm14,%xmm12

Reproducible: Always

Comment 1 Konstantin Tokarev 2013-07-15 17:49:18 UTC

Created attachment 81131 [details]
Test case which reproduces illegal instruction (does not work with current trunk as well)

Comment 2 Konstantin Tokarev 2013-07-15 17:55:10 UTC

Created attachment 81132 [details]
Result of compilation

Comment 3 ake.sandgren 2014-01-22 07:17:59 UTC

Looks like it is fixed in 3.9.0, at least my test cases no longer trip

Comment 4 Tom Hughes 2014-01-23 12:26:11 UTC

I think your compiler has just changed what code it is generating - the instruction here is a VEX prefixed version of "0F 3A 6B" and that does not appear to be implemented in the current code, which would be consistent with it being an AMD extension. Certainly that instruction is not documented in the Intel manual.

Comment 5 ake.sandgren 2014-01-23 12:55:33 UTC

It's even more likely that i messed up which test case belonged to which problem :-(

Yeah, the problem is still there in 3.9.0, and yes, that's from AMD's FMA4 instruction set.

I would really like it if it could get implemented.

Comment 6 Tom Hughes 2014-01-23 13:24:57 UTC

I suspect it's unlikely unless somebody who wants it steps up to do it, or unless those extensions gain a lot more traction.

Comment 7 Mark Wielaard 2021-02-28 18:34:00 UTC

This was added as part of bug #369000 for 128bit FMA4 instructions, 256bit FMA4 instructions aren't supported yet and are tracked as bug #369053

*** This bug has been marked as a duplicate of bug 369000 ***