https://bugs.llvm.org/show_bug.cgi?id=44377
Bug ID: 44377
Summary: Missing tail call for memcpy create by
LoopIdiomRecognizer
Product: libraries
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: enhancement
Priority: P
Component: Loop Optimizer
Assignee: unassignedb...@nondot.org
Reporter: david.bolvan...@gmail.com
CC: llvm-bugs@lists.llvm.org
void f(unsigned char*__restrict p,unsigned char*__restrict q,int n){
for(int i=0;i<n;++i)
p[i]=q[i];
}
Current -O3 codegen:
f(unsigned char*, unsigned char*, int): # @f(unsigned char*, unsigned char*,
int)
test edx, edx
jle .LBB0_2
push rax
mov edx, edx
call memcpy
add rsp, 8
.LBB0_2:
ret
But we could have a tail cail here:
f(unsigned char*, unsigned char*, int): # @f(unsigned char*, unsigned char*,
int)
test edx, edx
je .LBB0_1
movsxd rdx, edx
jmp memcpy # TAILCALL
.LBB0_1:
ret
--
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