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Merging r366868:

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r366868 | rogfer01 | 2019-07-24 07:33:46 +0200 (Wed, 24 Jul 2019) | 6 lines

[RISCV] Implement benchmark::cycleclock::Now

This is a cherrypick of D64237 onto llvm/utils/benchmark and
libcxx/utils/google-benchmark.

Differential Revision: https://reviews.llvm.org/D65142
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git-svn-id: https://llvm.org/svn/llvm-project/libcxx/branches/release_90@367813 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hans Wennborg
2019-08-05 08:14:21 +00:00
parent cd281462e2
commit 1d53e6cb6d
2 changed files with 21 additions and 0 deletions
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6
utils/google-benchmark/README.LLVM
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@@ -4,3 +4,9 @@ LLVM notes
This directory contains the Google Benchmark source code with some unnecessary This directory contains the Google Benchmark source code with some unnecessary
files removed. Note that this directory is under a different license than files removed. Note that this directory is under a different license than
libc++. libc++.
Changes:
* https://github.com/google/benchmark/commit/4abdfbb802d1b514703223f5f852ce4a507d32d2
is applied on top of
https://github.com/google/benchmark/commit/4528c76b718acc9b57956f63069c699ae21edcab
to add RISC-V timer support.

15
utils/google-benchmark/src/cycleclock.h
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@@ -164,6 +164,21 @@ inline BENCHMARK_ALWAYS_INLINE int64_t Now() {
uint64_t tsc; uint64_t tsc;
asm("stck %0" : "=Q"(tsc) : : "cc"); asm("stck %0" : "=Q"(tsc) : : "cc");
return tsc; return tsc;
#elif defined(__riscv) // RISC-V
// Use RDCYCLE (and RDCYCLEH on riscv32)
#if __riscv_xlen == 32
uint64_t cycles_low, cycles_hi0, cycles_hi1;
asm("rdcycleh %0" : "=r"(cycles_hi0));
asm("rdcycle %0" : "=r"(cycles_lo));
asm("rdcycleh %0" : "=r"(cycles_hi1));
// This matches the PowerPC overflow detection, above
cycles_lo &= -static_cast<int64_t>(cycles_hi0 == cycles_hi1);
return (cycles_hi1 << 32) | cycles_lo;
#else
uint64_t cycles;
asm("rdcycle %0" : "=r"(cycles));
return cycles;
#endif
#else #else
// The soft failover to a generic implementation is automatic only for ARM. // The soft failover to a generic implementation is automatic only for ARM.
// For other platforms the developer is expected to make an attempt to create // For other platforms the developer is expected to make an attempt to create