[Bug Target/105617] New: Regression In Code Generation For ...

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already5chosen at yahoo dot com via Gcc-bugs Mon, 16 May 2022 05:09:03 -0700

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105617 Bug ID: 105617 Summary: Regression in code generation for _addcarry_u64() Product: gcc Version: 12.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: already5chosen at yahoo dot com Target Milestone: --- It took many years until gcc caught up with MSVC and LLVM/clang in generation of code for chains of Intel's _addcarry_u64() intrinsic calls. But your finally managed to do it in gcc11. Unfortunately, the luck didn't last for long. void add4i(uint64_t dst[4], const uint64_t srcA[4], const uint64_t srcB[4]) { unsigned char c; unsigned long long r0; c = _addcarry_u64(0, srcA[0], srcB[0], &r0); unsigned long long r1; c = _addcarry_u64(c, srcA[1], srcB[1], &r1); unsigned long long r2; c = _addcarry_u64(c, srcA[2], srcB[2], &r2); unsigned long long r3; c = _addcarry_u64(c, srcA[3], srcB[3], &r3); dst[0] = r0; dst[1] = r1; dst[2] = r2; dst[3] = r3; } gcc 11.1 -O2 add4i: movq (%rdx), %rax addq (%rsi), %rax movq 8(%rsi), %rcx movq %rax, %r8 adcq 8(%rdx), %rcx movq 16(%rsi), %rax adcq 16(%rdx), %rax movq 24(%rdx), %rdx adcq 24(%rsi), %rdx movq %r8, (%rdi) movq %rcx, 8(%rdi) movq %rax, 16(%rdi) movq %rdx, 24(%rdi) ret gcc 12.1 -O2 add4i: movq (%rdx), %rax movq 8(%rsi), %rcx addq (%rsi), %rax movq 16(%rsi), %r8 adcq 8(%rdx), %rcx adcq 16(%rdx), %r8 movq %rax, %xmm1 movq 24(%rdx), %rdx adcq 24(%rsi), %rdx movq %r8, %xmm0 movq %rcx, %xmm3 movq %rdx, %xmm2 punpcklqdq %xmm3, %xmm1 punpcklqdq %xmm2, %xmm0 movups %xmm1, (%rdi) movups %xmm0, 16(%rdi) ret What ... ?! BTW, gcc 12.1 -O1 is still o.k.

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• [Bug target/105617] New: Regr... already5chosen at yahoo dot com via Gcc-bugs
• • [Bug target/105617] [12/... pinskia at gcc dot gnu.org via Gcc-bugs
  • [Bug target/105617] [12/... pinskia at gcc dot gnu.org via Gcc-bugs
  • [Bug target/105617] [12/... rguenth at gcc dot gnu.org via Gcc-bugs
  • [Bug target/105617] [12/... already5chosen at yahoo dot com via Gcc-bugs
  • [Bug target/105617] [12/... already5chosen at yahoo dot com via Gcc-bugs
  • [Bug target/105617] [12/... already5chosen at yahoo dot com via Gcc-bugs
  • [Bug target/105617] [12/... crazylht at gmail dot com via Gcc-bugs
  • [Bug target/105617] [12/... crazylht at gmail dot com via Gcc-bugs
  • [Bug target/105617] [12/... crazylht at gmail dot com via Gcc-bugs
  • [Bug target/105617] [12/... rguenth at gcc dot gnu.org via Gcc-bugs

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