- $p =~ s/^\tpushl\s+\%edi\n//;
- $p =~ s/^\tpushl\s+\%esi\n//;
- $p =~ s/^\tpushl\s+\%ebx\n//;
- $p =~ s/^\tmovl\s+\%esi,\s*\d*\(\%esp\)\n//;
- $p =~ s/^\tmovl\s+\%edi,\s*\d*\(\%esp\)\n//;
+ # gcc 3.4.3 puts this kind of stuff in the prologue, eg.
+ # when compiling PrimOps.cmm with -optc-O2:
+ # xorl %ecx, %ecx
+ # xorl %edx, %edx
+ # movl %ecx, 16(%esp)
+ # movl %edx, 20(%esp)
+ # but then the code of the function doesn't assume
+ # anything about the contnets of these stack locations.
+ # I think it's to do with the use of inline functions for
+ # PK_Word64() and friends, where gcc is initialising the
+ # contents of the struct to zero, and failing to optimise
+ # away the initialisation. Let's live dangerously and
+ # discard these initalisations.
+
+ $p =~ s/^\tpushl\s+\%e(di|si|bx)\n//g;
+ $p =~ s/^\txorl\s+\%e(ax|cx|dx),\s*\%e(ax|cx|dx)\n//g;
+ $p =~ s/^\tmovl\s+\%e(ax|cx|dx|si|di),\s*\d*\(\%esp\)\n//g;
+ $p =~ s/^\tmovl\s+\$\d+,\s*\d*\(\%esp\)\n//g;