------- Comment #21 from ubizjak at gmail dot com 2008-02-06 19:10 ------- (In reply to comment #20)
> Since -fo-f-p adds another free reg, it looks that since inlining increases > register pressure some unlucky heavy-used variable gets allocated to the stack > slot. It is "best_len" (and probably some others, too): [EMAIL PROTECTED] gzip-1.2.4]$ grep best_len fp.s movl %edx, -68(%ebp) #, best_len movl -68(%ebp), %edx # best_len, best_len.494 movl %edx, -68(%ebp) # best_len.494, best_len movl -68(%ebp), %edx # best_len, movl -68(%ebp), %edx # best_len, movl -68(%ebp), %edx # best_len, best_len.494 cmpl %esi, %edx # lookahead, best_len.494 movl %edx, -108(%ebp) # best_len.494, match_length movl -68(%ebp), %edx # best_len, best_len.494 movl %edx, -88(%ebp) # prev_length.28, best_len movl -88(%ebp), %edx # best_len, best_len.457 movl %edx, -88(%ebp) # best_len.457, best_len movl -88(%ebp), %eax # best_len, movl -88(%ebp), %edx # best_len, movl -88(%ebp), %edx # best_len, best_len.457 cmpl %esi, %edx # lookahead, best_len.457 movl %edx, -40(%ebp) # best_len.457, match_length.404 movl -88(%ebp), %edx # best_len, best_len.457 leal (%ecx,%eax), %edx #, best_len.457 cmpl %edx, -88(%ebp) # best_len.457, best_len cmpl -96(%ebp), %edx # nice_match.34, best_len.457 leal (%ecx,%eax), %edx #, best_len.494 cmpl %edx, -68(%ebp) # best_len.494, best_len cmpl -76(%ebp), %edx # nice_match.34, best_len.494 [EMAIL PROTECTED] gzip-1.2.4]$ grep best_len no-fp.s movl %edx, 76(%esp) #, best_len movl 76(%esp), %edx # best_len, movl 76(%esp), %edx # best_len, best_len.494 movl %edx, 76(%esp) # best_len.494, best_len movl 76(%esp), %eax # best_len, movl 76(%esp), %edx # best_len, best_len.494 movl %edx, %ebp # best_len.494, match_length movl 76(%esp), %edx # best_len, best_len.494 movl %edx, %ebp # prev_length.28, best_len movl %ebp, %edx # best_len, best_len.457 movl %edx, %ebp # best_len.457, best_len movl %ebp, %edx # best_len, best_len.457 cmpl %esi, %edx # lookahead, best_len.457 movl %ebp, %edx # best_len, best_len.457 leal (%ecx,%eax), %edx #, best_len.494 cmpl %edx, 76(%esp) # best_len.494, best_len cmpl 68(%esp), %edx # nice_match.34, best_len.494 leal (%ecx,%eax), %edx #, best_len.457 cmpl %edx, %ebp # best_len.457, best_len cmpl 52(%esp), %edx # nice_match.34, best_len.457 -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33761