diff options
Diffstat (limited to 'gcc/testsuite/gcc.wendy/gnu17.c')
| -rwxr-xr-x | gcc/testsuite/gcc.wendy/gnu17.c | 169 |
1 files changed, 0 insertions, 169 deletions
diff --git a/gcc/testsuite/gcc.wendy/gnu17.c b/gcc/testsuite/gcc.wendy/gnu17.c deleted file mode 100755 index d3b03c1..0000000 --- a/gcc/testsuite/gcc.wendy/gnu17.c +++ /dev/null @@ -1,169 +0,0 @@ -#if 0 -/* -Date: Mon, 17 Aug 87 09:03:50 PDT -From: bruce@stride.stride.com (Bruce Robertson) -To: bug-gcc@prep.ai.mit.edu -Subject: Optimizer bug in gcc 1.x - -I found the cause of the optimizer bug that I've been sending you. It -occurs because you scan for the first and last occurances of registers -before common subexpression processing, but cse can change these -occurances. The bug appears in the example program because loop -optimization removes a load of "mem" into a pseudo-register, because -based on the information of the register scan it thinks that there are -no more appearances of the pseudo-register. Cse added a reference, -however, and this information is not placed in regno_last_uid[]. The -solution seems to be to call reg_scan() again after calling -cse_main(). It fixed the bug anyway, and didn't seem to cause -anything bad. - -Diffs for the fix, and the original sample program follow. - - -Diffs: -====================================================================== -*** /tmp/,RCSt1a00495 Thu Aug 13 13:09:01 1987 ---- toplev.c Thu Aug 13 13:08:39 1987 -*************** -*** 776,781 **** ---- 776,786 ---- - - TIMEVAR (cse_time, tem = cse_main (insns, max_reg_num ())); - -+ /* We need to scan for registers again, because common subexpression -+ elimination could have rearranged the first and last occurrances -+ of registers. */ -+ TIMEVAR (cse_time, reg_scan (insns, max_reg_num ())); -+ - if (tem) - TIMEVAR (jump_time, jump_optimize (insns, 0, 0)); - } - - - -Sample program: -====================================================================== -#endif - -typedef unsigned char quarterword; -typedef unsigned short halfword; - -typedef union -{ - struct { - halfword lh; - halfword rh; - } hh1; - struct { - quarterword b0; - quarterword b1; - halfword rh; - } hh2; -} - two_halves; - -typedef struct -{ - quarterword b0; - quarterword b1; - quarterword b2; - quarterword b3; -} - four_quarters; - -typedef union -{ - int i; - float gr; - two_halves hh; - four_quarters qqqq; -} - memory_word; - -memory_word mem[10]; - -unsigned int fewest_demerits; -unsigned short best_bet = 0; -unsigned short best_line = -1; - - -void -foo(r) - unsigned short r; -{ - - do { - if (mem[r].hh.hh2.b0 != 2 && - mem[(r) + 2].i < fewest_demerits) { - best_bet = r; - } - r = mem[r].hh.hh1.rh; - } while (r != (65501 - 7)); - - /* - * This is the statement that is causing trouble. See the comment - * in the assembly code below. - */ - best_line = mem[best_bet + 1].hh.hh1.lh; -} - -main() -{ - mem[0].hh.hh2.b0 = 0; - mem[0].hh.hh1.rh = 65501-7; - mem[1].hh.hh1.lh = 456; - mem[2].i = 30; - foo(0); - if (best_line == 456) - printf("Test passed\n"); - else - printf("Test failed, best_line = %d\n", best_line); -} - -/* - -#NO_APP -.comm _fewest_demerits,4 -.comm _best_bet,2 -.comm _best_line,2 -.globl _foo -.text - .even -_foo: - link a6,#0 - moveml #0x3000,sp@- - movew #1,d0 - clrl d1 - clrl d2 - lea _mem,a0 -L2: - movew d0,d1 - cmpb #2,a0@(d1:l:4) - jeq L4 - movel a0@(8,d1:l:4),d3 - cmpl _fewest_demerits,d3 - jcc L4 - movew d0,_best_bet -L4: - movew d0,d2 - movew a0@(2,d2:l:4),d0 - cmpw #65494,d0 - jne L2 - clrl d0 - movew _best_bet,d0 - -| -| Where did this reference (below) to A1 come from? It should be A0, -| since that still points to "mem". A1 is never set in the code -| above. -| -| When this code fragment is in place in Common Tex (in function -| "line_break()" in file "par.c") the reference is to -4(fp) -| rather than A1. -| - - movew a1@(4,d0:l:4),_best_line - moveml a6@(-8),#0xc - unlk a6 - rts -*/ |