[Bug rtl-optimization/35281] New: [4.3 regression] multiply with 0 generated for 64*32->64

["astrange at ithinksw dot com" <gcc-bugzilla at gcc dot gnu dot org>]

> /usr/local/gcc43/bin/gcc -v                                           
Using built-in specs.
Target: i386-apple-darwin9.2.0
Configured with: ../gcc/configure --prefix=/usr/local/gcc43
--enable-threads=posix --with-arch=core2 --with-tune=core2 --with-gmp=/sw
--with-mpfr=/sw --disable-nls --disable-bootstrap --enable-checking=yes,rtl
CFLAGS=-g LDFLAGS=/usr/lib/libiconv.dylib --enable-languages=c,c++,objc,obj-c++
Thread model: posix
gcc version 4.4.0 20080219 (experimental) (GCC) 
> /usr/local/gcc43/bin/gcc -Os -fno-PIC -S u64mul.c -fomit-frame-pointer

gcc generates:
_mul32:
        pushl   %ebx
        xorl    %edx, %edx
        subl    $8, %esp
        movl    _b, %eax
        movl    _a, %ecx
        movl    _a+4, %ebx
        imull   %edx, %ecx
        imull   %eax, %ebx
        mull    _a
        addl    %ebx, %ecx
        leal    (%ecx,%edx), %edx
        popl    %ecx
        popl    %ebx
        popl    %ebx
        ret

and somehow leaves all the stuff with edx in.
4.1.3 generates:
mul32:
        movl    _b, %eax
        movl    _a+4, %ecx
        imull   %eax, %ecx
        mull    _a
        addl    %edx, %ecx
        movl    %ecx, %edx
        ret

They both generate bad code for mul16.


-- 
           Summary: [4.3 regression] multiply with 0 generated for 64*32->64
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: astrange at ithinksw dot com
 GCC build triplet: i386-apple-darwin9.2.0
  GCC host triplet: i386-apple-darwin9.2.0
GCC target triplet: i386-apple-darwin9.2.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35281