IR build failed with "-O0" but succeeded with "-O2" option

[stkeke]

The IR function below failed to compile with -O0 option, but okay with -O2 option.

Failed IR program

tony@Win11Z790I:~/ir$ cat t.ir
{
        uintptr_t c_1 = 0;
        bool c_2 = 0;
        bool c_3 = 1;
        int32_t c_4 = 1;
        int32_t c_5 = 2;
        l_1 = START(l_20);
        bool d_2 = PARAM(l_1, "cond", 0);
        bool d_3 = COPY(c_4);
        l_4 = END(l_1);
        l_5 = LOOP_BEGIN(l_4, l_18);
        int32_t d_6 = PHI(l_5, d_3, d_15);
        bool d_7 = NE(d_6, c_4);
        l_8 = IF(l_5, d_7);
        l_9 = IF_TRUE(l_8);
        int32_t d_10 = COPY(c_5);
        l_11 = END(l_9);
        l_12 = IF_FALSE(l_8);
        l_13 = END(l_12);
        l_14 = MERGE(l_11, l_13);
        int32_t d_15 = PHI(l_14, d_10, d_6);
        l_16 = IF(l_14, d_2);
        l_17 = IF_TRUE(l_16);
        l_18 = LOOP_END(l_17);
        l_19 = IF_FALSE(l_16);
        l_20 = RETURN(l_19, d_15);
}

tony@Win11Z790I:~/ir$ ~/ir/ir t.ir  -O0 --save 
ir_base[6].ops[2] (3) type is incompatible with result type (1 != 10)
ir: ir_check.c:347: ir_check: Assertion `ok' failed.
Aborted

tony@Win11Z790I:~/ir$ ~/ir/ir t.ir  -O2 --save 
{
        uintptr_t c_1 = 0;
        bool c_2 = 0;
        bool c_3 = 1;
        int32_t c_4 = 1;
        l_1 = START(l_9);
        bool d_2 = PARAM(l_1, "cond", 0);
        l_3 = END(l_1);
        l_4 = LOOP_BEGIN(l_3, l_7);
        l_5 = IF(l_4, d_2);
        l_6 = IF_TRUE(l_5);
        l_7 = LOOP_END(l_6);
        l_8 = IF_FALSE(l_5);
        l_9 = RETURN(l_8, c_4);
}

DO NOT USE for Reproduce

This is the good -O2 dump --- sorry for paste wrong program in first report.

tony@Win11Z790I:~/ir$ cat t.ir
{
        uintptr_t c_1 = 0;
        bool c_2 = 0;
        bool c_3 = 1;
        int32_t c_4 = 1;
        l_1 = START(l_9);
        bool d_2 = PARAM(l_1, "cond", 0);
        l_3 = END(l_1);
        l_4 = LOOP_BEGIN(l_3, l_7);
        l_5 = IF(l_4, d_2);
        l_6 = IF_TRUE(l_5);
        l_7 = LOOP_END(l_6);
        l_8 = IF_FALSE(l_5);
        l_9 = RETURN(l_8, c_4);
}

tony@Win11Z790I:~/ir$ ./ir -O0 t.ir --save
ir_base[6].ops[2] (3) type is incompatible with result type (1 != 10)
ir: ir_check.c:347: ir_check: Assertion `ok' failed.
Aborted

tony@Win11Z790I:~/ir$ ./ir -O2 t.ir --save
{
        uintptr_t c_1 = 0;
        bool c_2 = 0;
        bool c_3 = 1;
        int32_t c_4 = 1;
        l_1 = START(l_9);
        bool d_2 = PARAM(l_1, "cond", 0);
        l_3 = END(l_1);
        l_4 = LOOP_BEGIN(l_3, l_7);
        l_5 = IF(l_4, d_2);
        l_6 = IF_TRUE(l_5);
        l_7 = LOOP_END(l_6);
        l_8 = IF_FALSE(l_5);
        l_9 = RETURN(l_8, c_4);
}

[dstogov]

ir_base[6].ops[2] (3) type is incompatible with result type (1 != 10)

I can't reproduce this. I also don't see how this error might be emitted at all.
It indicates type check failure for instruction number 6 - l_6 = IF_TRUE(l_5);, but we don't not check result type of IF_TRUE.

[dstogov]

There is a error in the original program at bool d_3 = COPY(c_4);.
bool should be replaced by int32_t.
ir -O0 just detected that error.
It seems ir -O2 optimized out the problematic COPY before the check.

[stkeke]

I tried to place ir_check(ctx); (suppose this function do the check) to the front of ir_compile_func function.
But still has the issue... did not catch the error with -O2.

tony@Win11Z790I:~/ir$ ./ir -O2 t.ir --save
{
        uintptr_t c_1 = 0;
        bool c_2 = 0;
        bool c_3 = 1;
        int32_t c_4 = 1;
        l_1 = START(l_9);
        bool d_2 = PARAM(l_1, "cond", 0);
        l_3 = END(l_1);
        l_4 = LOOP_BEGIN(l_3, l_7);
        l_5 = IF(l_4, d_2);
        l_6 = IF_TRUE(l_5);
        l_7 = LOOP_END(l_6);
        l_8 = IF_FALSE(l_5);
        l_9 = RETURN(l_8, c_4);
}

https://github.com/dstogov/ir/blob/master/ir_main.c#L151

// ir_main.c https://github.com/dstogov/ir/blob/master/ir_main.c#L151
int ir_compile_func(ir_ctx *ctx, int opt_level, uint32_t dump, const char *dump_file)
{
	ir_check(ctx); // Check before optimization - hope to catch error even with -O2

	if ((dump & (IR_DUMP_AFTER_LOAD|IR_DUMP_AFTER_ALL))
	 && !_save(ctx, dump, IR_DUMP_AFTER_LOAD, dump_file)) {
		return 0;
	}

	if (opt_level > 0 || (ctx->flags & (IR_GEN_NATIVE|IR_GEN_C))) {
		ir_build_def_use_lists(ctx);
	}

	/* Global Optimization */
	if (opt_level > 1) {
...
	ir_check(ctx); // After optimization check

	return 1;
}

[dstogov]

The COPY is eliminated by folding engine that works on the fly during IR construction or loading.
See https://github.com/dstogov/ir/blob/master/ir_fold.h#L1153
We may catch this error at the body of the rule adding IR_ASSERT(IR_OPT_TYPE(opt) == op1_insn->type);

See 75edc8f

I think, this issue may be closed

[stkeke]

@dstogov Thanks. Let's close it as "Fixed".