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https://github.com/c64scene-ar/llvm-6502.git
synced 2024-07-22 09:29:31 +00:00
LLVM backend for 6502
62fe406dc2
This fixes rdar://8808586 which observed that we used to compile:
union xy {
struct x { _Bool b[15]; } x;
__attribute__((packed))
struct y {
__attribute__((packed)) unsigned long b0to7;
__attribute__((packed)) unsigned int b8to11;
__attribute__((packed)) unsigned short b12to13;
__attribute__((packed)) unsigned char b14;
} y;
};
struct x
foo(union xy *xy)
{
return xy->x;
}
into:
_foo: ## @foo
movq (%rdi), %rax
movabsq $1095216660480, %rcx ## imm = 0xFF00000000
andq %rax, %rcx
movabsq $-72057594037927936, %rdx ## imm = 0xFF00000000000000
andq %rax, %rdx
movzbl %al, %esi
orq %rdx, %rsi
movq %rax, %rdx
andq $65280, %rdx ## imm = 0xFF00
orq %rsi, %rdx
movq %rax, %rsi
andq $16711680, %rsi ## imm = 0xFF0000
orq %rdx, %rsi
movl %eax, %edx
andl $-16777216, %edx ## imm = 0xFFFFFFFFFF000000
orq %rsi, %rdx
orq %rcx, %rdx
movabsq $280375465082880, %rcx ## imm = 0xFF0000000000
movq %rax, %rsi
andq %rcx, %rsi
orq %rdx, %rsi
movabsq $71776119061217280, %r8 ## imm = 0xFF000000000000
andq %r8, %rax
orq %rsi, %rax
movzwl 12(%rdi), %edx
movzbl 14(%rdi), %esi
shlq $16, %rsi
orl %edx, %esi
movq %rsi, %r9
shlq $32, %r9
movl 8(%rdi), %edx
orq %r9, %rdx
andq %rdx, %rcx
movzbl %sil, %esi
shlq $32, %rsi
orq %rcx, %rsi
movl %edx, %ecx
andl $-16777216, %ecx ## imm = 0xFFFFFFFFFF000000
orq %rsi, %rcx
movq %rdx, %rsi
andq $16711680, %rsi ## imm = 0xFF0000
orq %rcx, %rsi
movq %rdx, %rcx
andq $65280, %rcx ## imm = 0xFF00
orq %rsi, %rcx
movzbl %dl, %esi
orq %rcx, %rsi
andq %r8, %rdx
orq %rsi, %rdx
ret
We now compile this into:
_foo: ## @foo
## BB#0: ## %entry
movzwl 12(%rdi), %eax
movzbl 14(%rdi), %ecx
shlq $16, %rcx
orl %eax, %ecx
shlq $32, %rcx
movl 8(%rdi), %edx
orq %rcx, %rdx
movq (%rdi), %rax
ret
A small improvement :-)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123520 91177308-0d34-0410-b5e6-96231b3b80d8
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