[Bug rtl-optimization/69633] [6 Regression] Redundant move is generated after r228097

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69633

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |NEW
   Last reconfirmed|                            |2016-03-09
         Resolution|INVALID                     |---
     Ever confirmed|0                           |1

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Strange, I can still reproduce it:
./cc1.228094 -quiet -O2 -m32 -fPIE pr69633.c -o pr69633.s1 -march=i386 \
-mtune=generic
./cc1.228097 -quiet -O2 -m32 -fPIE pr69633.c -o pr69633.s2 -march=i386 \
-mtune=generic
./cc1.228153 -quiet -O2 -m32 -fPIE pr69633.c -o pr69633.s3 -march=i386 \
-mtune=generic
./cc1.234064 -quiet -O2 -m32 -fPIE pr69633.c -o pr69633.s4 -march=i386 \
-mtune=generic
Compared to the first one, all the others have one more instruction in the
function.
E.g. between s1 and s3 there is:
@@ -44,17 +41,18 @@ foo:
        addl    %edi, %ebx
        imull   $7471, %ecx, %edi
        leal    32768(%ebx,%edi), %ebx
-       imull   $-15119, %eax, %edi
        sarl    $16, %ebx
        movb    %bl, -3(%ebp)
        movl    %edx, %ebx
        sall    $15, %ebx
-       subl    %edx, %ebx
+       movl    %ebx, %edi
+       imull   $-15119, %eax, %ebx
+       subl    %edx, %edi
+       imull   $13282, %edx, %edx
        addl    %edi, %ebx
        imull   $-17648, %ecx, %edi
-       imull   $13282, %edx, %edx
-       leal    32768(%ebx,%edi), %ebx
        imull   $19485, %ecx, %ecx
+       leal    32768(%ebx,%edi), %ebx
        sarl    $16, %ebx
        movb    %bl, -2(%ebp)
        movl    %eax, %ebx
s1 to s4 has more changes, but also one more instruction.