[Bug target/66749] New: [4.9/5/6] gcc.target/i386/addr-sel-1.c fails to merge array index into one instruction with -m32 -mregparm=3 or with -miamcu

[Bug target/66749] New: [4.9/5/6] gcc.target/i386/addr-sel-1.c fails to merge array index into one instruction with -m32 -mregparm=3 or with -miamcu

[julia.koval at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66749

            Bug ID: 66749
           Summary: [4.9/5/6] gcc.target/i386/addr-sel-1.c fails to merge
                    array index into one instruction with -m32 -mregparm=3
                    or with -miamcu
           Product: gcc
           Version: 4.9.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: julia.koval at intel dot com
  Target Milestone: ---

The test tries to generate code for:
return a[i+1] + b[i+1];

For -m32 gcc generates proper code:
movl    4(%esp), %eax
movsbl  a+1(%eax), %ecx
movsbl  b+1(%eax), %eax
addl    %ecx, %eax

However with -m32 -mregparm=3 the b value fails to be combined:
movsbl  a+1(%eax), %edx
incl    %eax
movsbl  b(%eax), %eax
addl    %edx, %eax

The error also remains with -mregparm=1/2 or with -miamcu.

[Bug target/66749] [4.9/5/6] gcc.target/i386/addr-sel-1.c fails to merge array index into one instruction with -m32 -mregparm=3 or with -miamcu

[julia.koval at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66749

--- Comment #1 from Yulia Koval <julia.koval at intel dot com> ---
Reproduce:
./gcc -Bgcc addr-sel-1.c -O2 -m32 -mregparm=3 -mtune=i686 -S -o addr-sel-1.s

-mtune=i686 is dg-option of the test.

[Bug target/66749] [4.9/5/6] gcc.target/i386/addr-sel-1.c fails to merge array index into one instruction with -m32 -mregparm=3 or with -miamcu

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66749

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hjl.tools at gmail dot com
            Version|4.9.3                       |6.0
   Target Milestone|---                         |6.0

[Bug target/66749] [4.9/5/6] gcc.target/i386/addr-sel-1.c fails to merge array index into one instruction with -m32 -mregparm=3 or with -miamcu

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66749

--- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> ---
Created attachment 35904
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35904&action=edit
A patch

Please try this.

[Bug target/66749] [4.9/5/6] gcc.target/i386/addr-sel-1.c fails to merge array index into one instruction with -m32 -mregparm=3 or with -miamcu

[julia.koval at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66749

--- Comment #5 from Yulia Koval <julia.koval at intel dot com> ---
(In reply to H.J. Lu from comment #4)
> Created attachment 35904 [details]
> A patch
> 
> Please try this.

It fixes the problem.

[Bug target/66749] [4.9/5/6] gcc.target/i386/addr-sel-1.c fails to merge array index into one instruction with -m32 -mregparm=3 or with -miamcu

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66749

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #7 from H.J. Lu <hjl.tools at gmail dot com> ---
Fixed for GCC 6.