x86_64: Remove redundant REX bytes from memrchr.S
By x86-64 specification, 32-bit destination registers are zero-extended to 64 bits. There is no need to use 64-bit registers when only the lower 32 bits are non-zero. Also 2 instructions in: mov %rdi, %rcx and $15, %rcx jz L(length_less16_offset0) mov %rdi, %rcx <<< redundant and $15, %rcx <<< redundant are redundant. * sysdeps/x86_64/memrchr.S (__memrchr): Use 32-bit registers for the lower 32 bits. Remove redundant instructions.
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7395928b95
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@ -1,3 +1,8 @@
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2017-06-05 H.J. Lu <hongjiu.lu@intel.com>
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* sysdeps/x86_64/memrchr.S (__memrchr): Use 32-bit registers for
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the lower 32 bits. Remove redundant instructions.
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2017-06-05 H.J. Lu <hongjiu.lu@intel.com>
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* sysdeps/unix/sysv/linux/x86_64/sysdep.h (LO_HI_LONG): Pass
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@ -22,7 +22,7 @@
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.text
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ENTRY (__memrchr)
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movd %rsi, %xmm1
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movd %esi, %xmm1
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sub $16, %rdx
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jbe L(length_less16)
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@ -42,8 +42,8 @@ ENTRY (__memrchr)
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jnz L(matches0)
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sub $64, %rdi
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mov %rdi, %rcx
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and $15, %rcx
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mov %edi, %ecx
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and $15, %ecx
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jz L(loop_prolog)
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add $16, %rdi
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@ -108,8 +108,8 @@ L(loop_prolog):
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test %eax, %eax
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jnz L(matches0)
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mov %rdi, %rcx
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and $63, %rcx
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mov %edi, %ecx
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and $63, %ecx
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jz L(align64_loop)
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add $64, %rdi
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@ -166,8 +166,8 @@ L(align64_loop):
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.p2align 4
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L(exit_loop):
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add $64, %rdx
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cmp $32, %rdx
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add $64, %edx
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cmp $32, %edx
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jbe L(exit_loop_32)
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movdqa 48(%rdi), %xmm0
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@ -187,7 +187,7 @@ L(exit_loop):
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pmovmskb %xmm3, %eax
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test %eax, %eax
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jnz L(matches16_1)
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cmp $48, %rdx
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cmp $48, %edx
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jbe L(return_null)
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pcmpeqb (%rdi), %xmm1
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@ -204,7 +204,7 @@ L(exit_loop_32):
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pmovmskb %xmm0, %eax
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test %eax, %eax
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jnz L(matches48_1)
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cmp $16, %rdx
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cmp $16, %edx
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jbe L(return_null)
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pcmpeqb 32(%rdi), %xmm1
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@ -276,7 +276,7 @@ L(matches48_1):
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.p2align 4
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L(return_null):
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xor %rax, %rax
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xor %eax, %eax
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ret
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.p2align 4
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@ -306,18 +306,16 @@ L(length_less16):
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punpcklbw %xmm1, %xmm1
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punpcklbw %xmm1, %xmm1
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add $16, %rdx
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add $16, %edx
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pshufd $0, %xmm1, %xmm1
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mov %rdi, %rcx
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and $15, %rcx
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mov %edi, %ecx
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and $15, %ecx
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jz L(length_less16_offset0)
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mov %rdi, %rcx
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and $15, %rcx
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mov %cl, %dh
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mov %rcx, %r8
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mov %ecx, %esi
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add %dl, %dh
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and $-16, %rdi
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@ -340,7 +338,7 @@ L(length_less16):
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bsr %eax, %eax
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add %rdi, %rax
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add %r8, %rax
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add %rsi, %rax
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ret
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.p2align 4
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@ -362,14 +360,14 @@ L(length_less16_part2):
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pcmpeqb (%rdi), %xmm1
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pmovmskb %xmm1, %eax
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mov %r8, %rcx
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mov %esi, %ecx
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sar %cl, %eax
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test %eax, %eax
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jz L(return_null)
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bsr %eax, %eax
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add %rdi, %rax
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add %r8, %rax
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add %rsi, %rax
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ret
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.p2align 4
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