https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105448
Bug ID: 105448
Summary: load introduced when passing a struct as argument
Product: gcc
Version: 11.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: absoler at smail dot nju.edu.cn
Target Milestone: ---
Created attachment 52915
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52915&action=edit
C source file where a struct field has been loaded repeatedly
Hi, I find in this code: (the full file has been uploaded)
...
struct S0 {
const uint64_t f0;
int32_t f1;
int64_t f2;
int32_t f3;
int64_t f4;
const int32_t f5;
};
struct S0 g_19 = {0xF4275799D45EB447LL,0xD326D35DL,1L,1L,9L,0L};
...
const int16_t func_2(uint32_t p_3, const struct S1 p_4)
{
if (func_7(g_19, 0, g_20))
{
return 0;
}
return g_6.f1;
}
int32_t func_7(struct S0 p_10, uint32_t p_11, int32_t p_12)
{
func_21(0, g_26, p_10);
return p_10.f1;
}
int32_t func_21(int32_t p_22, int64_t p_23, struct S0 p_24)
{
if ((g_5[0] - (g_5[1] != p_23)) )
{
g_19.f3 = p_24.f4;
}
return g_5[4];
}
int main(){
...
func_2(0, g_6);
...
}
when compiled on gcc-11.3.0 with O1 option, func_2 will be compiled as:
...
0x000000000040118a <+5>: movdqa 0x2ece(%rip),%xmm0 # 0x404060
<g_19>
0x0000000000401192 <+13>: movaps %xmm0,(%rsp)
0x0000000000401196 <+17>: mov 0x2ecc(%rip),%ebx # 0x404068
<g_19+8>
0x000000000040119c <+23>: mov %ebx,0x8(%rsp)
0x00000000004011a0 <+27>: pushq 0x2ee2(%rip) # 0x404088 <g_19+40>
0x00000000004011a6 <+33>: pushq 0x2ed4(%rip) # 0x404080 <g_19+32>
0x00000000004011ac <+39>: pushq 0x2ec6(%rip) # 0x404078 <g_19+24>
0x00000000004011b2 <+45>: pushq 0x2eb8(%rip) # 0x404070 <g_19+16>
...
it's obvious that g_19.f1 has been loaded twice in the first and third
instruction abnormally.
