gcc/testsuite/gcc.dg/tree-ssa/alias_bug.c

   1 /* { dg-do compile } */
   2 /* { dg-options "-O2 -fno-strict-aliasing -fdump-tree-optimized" } */
   3
   4 typedef unsigned u32;
   5 typedef unsigned short u16;
   6 typedef unsigned char u8;
   7 struct biosregs {
   8  union {
   9   struct {
  10    u32 edi;
  11    u32 esi;
  12    u32 ebp;
  13    u32 _esp;
  14    u32 ebx;
  15    u32 edx;
  16    u32 ecx;
  17    u32 eax;
  18    u32 _fsgs;
  19    u32 _dses;
  20    u32 eflags;
  21   };
  22   struct {
  23    u16 di, hdi;
  24    u16 si, hsi;
  25    u16 bp, hbp;
  26    u16 _sp, _hsp;
  27    u16 bx, hbx;
  28    u16 dx, hdx;
  29    u16 cx, hcx;
  30    u16 ax, hax;
  31    u16 gs, fs;
  32    u16 es, ds;
  33    u16 flags, hflags;
  34   };
  35   struct {
  36    u8 dil, dih, edi2, edi3;
  37    u8 sil, sih, esi2, esi3;
  38    u8 bpl, bph, ebp2, ebp3;
  39    u8 _spl, _sph, _esp2, _esp3;
  40    u8 bl, bh, ebx2, ebx3;
  41    u8 dl, dh, edx2, edx3;
  42    u8 cl, ch, ecx2, ecx3;
  43    u8 al, ah, eax2, eax3;
  44   };
  45  };
  46 };
  47 void initregs(struct biosregs *regs);
  48 void intcall(u8 int_no, const struct biosregs *ireg, struct biosregs *oreg);
  49 static u32 *const gp = (u32*) 0x32;
  50 void keyboard_set_repeat(void)
  51 {
  52  struct biosregs ireg;
  53  *gp = 10;
  54  initregs(&ireg);
  55  ireg.ax = 0x0305;
  56  intcall(0x16, &ireg, ((void *)0));
  57 }
  58
  59 /* { dg-final { scan-tree-dump-times "ireg.*ax" 1 "optimized"} } */
  60