Bug#151196: gcc-2.95.4-9 ICE in kernel (matroxfb) code

[Petr Vandrovec <vandrove@vc.cvut.cz>]

Package: gcc-2.95
Version: 2.95.4-9

Hi,
  I removed debug prints from new matroxfb driver, and ... compiler 
died. Simplest example I was able to invent is below. If you uncomment
printf(), or if you'll remove (almost) any line from computeRegs() body, 
it will stop ICE.

  gcc-3.0 (3.0.4-10) and gcc-3.1 (3.1.1-0pre2) compile code flawlessly.

					Best regards,
						Petr Vandrovec
						vandrove@vc.cvut.cz


$ gcc-2.95 -W -Wall -O2 bug.c
bug.c: In function `computeRegs':
bug.c:72: Internal compiler error:
bug.c:72: internal error--unrecognizable insn:
(insn 62 61 151 (parallel[
            (set (reg:SI 0 %eax)
                (asm_operands ("") ("=a") 0[
                        (reg:DI 1 %edx)
                    ]
                    [
                        (asm_input:DI ("A"))
                    ]  ("bug.c") 60))
            (set (reg:SI 1 %edx)
                (asm_operands ("") ("=d") 1[
                        (reg:DI 1 %edx)
                    ]
                    [
                        (asm_input:DI ("A"))
                    ]  ("bug.c") 60))
        ] ) -1 (insn_list 57 (nil))
    (nil))
$

#define do_div(n,base) ({ \
	unsigned long __upper, __low, __high, __mod; \
	asm("":"=a" (__low), "=d" (__high):"A" (n)); \
	__upper = __high; \
	if (__high) { \
		__upper = __high % (base); \
		__high = __high / (base); \
	} \
	asm("divl %2":"=a" (__low), "=d" (__mod):"rm" (base), "0" (__low), "1" (__upper)); \
	asm("":"=A" (n):"a" (__low),"d" (__high)); \
	__mod; \
})

#define u_int32_t unsigned int

struct mavenregs {
	unsigned char regs[256];
};

struct my_timming {
	u_int32_t HDisplay;
	unsigned int pixclock;
	unsigned int mnp;
};

struct output_desc {
	unsigned int	h_vis;
	unsigned int	h_f_porch;
	unsigned int	h_sync;
	unsigned int	h_b_porch;
	unsigned long long int	chromasc;
	unsigned int	burst;
	unsigned int	v_total;
};

unsigned int matroxfb_g450_setclk(unsigned int, unsigned int);
unsigned int g450_mnp2f(unsigned int);

static void computeRegs(struct mavenregs* r, struct my_timming* mt, const struct output_desc* outd) {
	u_int32_t chromasc;
	u_int32_t hlen;
	u_int32_t hfp;
	u_int32_t hvis;
	unsigned int pixclock;
	unsigned long long piic;
	int mnp;

	hvis = 1;
	piic = 1000000000ULL * hvis;

	mnp = matroxfb_g450_setclk(piic, 3);
	
	mt->pixclock = g450_mnp2f(mnp);
//	printf("PX: %u\n", mt->pixclock);
	mt->mnp = mnp;

	pixclock = 1000000000U / mt->pixclock;

	piic = outd->chromasc;
	do_div(piic, mt->pixclock);
	chromasc = piic;

	r->regs[0] = chromasc >> 24;
	r->regs[1] = chromasc >> 16;

	hfp = (((outd->h_f_porch + pixclock) / pixclock)) & ~1;
	hlen = hvis + hfp;

	if (hlen) {
		hfp -= hlen;
	}
}




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