Bug 233638

Summary:	Unhandled instructions bytes: 0x48 0xF 0xFE 0x7E 0x70 0x48
Product:	[Developer tools] valgrind	Reporter:	Sebastien Cote <sebas642>
Component:	vex	Assignee:	Julian Seward <jseward>
Status:	REPORTED ---
Severity:	crash	CC:	cpigat242
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Compiled Sources
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Bug Depends on:
Bug Blocks:	253451
Attachments:	workaround for rex.W prefix

Description Sebastien Cote 2010-04-07 20:14:32 UTC

Version:           SVN r1969 (using Devel)
OS:                Linux
Installed from:    Compiled sources

Running valgrind on an application using Intel Performance Primitive libraries, valgrind exits with the following message:

vex amd64->IR: unhandled instruction bytes: 0x48 0xF 0xFE 0x7E 0x70 0x48
==23588== valgrind: Unrecognised instruction at address 0x17783a16.

This can be reproduced with valgrind r11100 and VEX r1969.

Running objdump -d on the library and grepping for these bytes, I get the following instruction:

8e1a4:       48 0f fe 7e 70          rex.W paddd  0x70(%rsi),%mm7

Comment 1 Sebastien Cote 2010-04-07 20:17:39 UTC

I also get another unhandled instruction with IPP (in a different part of the code):

vex amd64->IR: unhandled instruction bytes: 0x48 0xF 0xFC 0xD 0x77 0x8A
==21616== valgrind: Unrecognised instruction at address 0x182e0171.


I get the following from objdump:
65171:   48 0f fc 0d 77 8a 24   rex.W paddb  0x248a77(%rip),%mm1    # 2adbf0 <const_array_of_127b>


I can open another bug for the second instruction if it matters.

Comment 2 Sebastien Cote 2010-04-17 16:45:35 UTC

Created attachment 42847 [details]
workaround for rex.W prefix

Attached workaround for the REX.W prefix. The PMOVMSKB instruction is just ignored for now but with these changes my application can run inside valgrind with memcheck.