3d7df0a547
This patch fixes the compilation time issue of matrix-types-spec test from test-suite. Reproduction of the problem: ``` clang++ -DNDEBUG --target=riscv64-linux-gnu --sysroot=<sysroot path> --gcc-toolchain=<gcc path> -O2 -fenable-matrix <test-suite-path>/SingleSource/UnitTests/matrix-types-spec.cpp ``` On my machine, compilation takes 50.44s. In comparison, the same test with RVV (-march=rv64gcv) compiles in 3.06s, and for x86-64 target it takes 1.71s. It turns out that the main issue is unrolling of loop in multiplySpec function, that has extractelements with non-constant index: ``` for.body9.i: ; preds = %for.body9.i, %for.cond6.preheader.i %indvars.iv.i92 = phi i64 [ 0, %for.cond6.preheader.i ], [ %indvars.iv.next.i93, %for.body9.i ] %Elt.033.i = phi double [ 0.000000e+00, %for.cond6.preheader.i ], [ %80, %for.body9.i ] %77 = mul nuw nsw i64 %indvars.iv.i92, 25 %78 = add nuw nsw i64 %77, %indvars.iv39.i91 %matrixext.i = extractelement <475 x double> %62, i64 %78 %79 = add nuw nsw i64 %indvars.iv.i92, %74 %matrixext13.i = extractelement <209 x double> %73, i64 %79 %80 = tail call double @llvm.fmuladd.f64(double %matrixext.i, double %matrixext13.i, double %Elt.033.i) %indvars.iv.next.i93 = add nuw nsw i64 %indvars.iv.i92, 1 %exitcond.not.i94 = icmp eq i64 %indvars.iv.next.i93, 19 br i1 %exitcond.not.i94, label %for.cond.cleanup8.i, label %for.body9.i, !llvm.loop !21 ``` When RVV is supported, extractelement/insertelement with non-constant index can be lowered quite efficiently with vslidedown/vslideup; otherwise it's lowered via stack memory operations, i.e. for extractelement each vector element is stored on stack and then the needed element is loaded back; for insertelement is stores all vector elements, rewrites the required element value and then loads vector back. Currently the cost of such expensive operation is estimated as zero, so loop unroll processes the loop more aggresively. The proper estimation of cost (in a way like in X86 target) prohibits unrolling of this loop and fixes compilation time (2.77s on my machine). |
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| .ci | ||
| .github | ||
| bolt | ||
| clang | ||
| clang-tools-extra | ||
| cmake | ||
| compiler-rt | ||
| cross-project-tests | ||
| flang | ||
| libc | ||
| libclc | ||
| libcxx | ||
| libcxxabi | ||
| libunwind | ||
| lld | ||
| lldb | ||
| llvm | ||
| llvm-libgcc | ||
| mlir | ||
| openmp | ||
| polly | ||
| pstl | ||
| runtimes | ||
| third-party | ||
| utils | ||
| .arcconfig | ||
| .arclint | ||
| .clang-format | ||
| .clang-tidy | ||
| .git-blame-ignore-revs | ||
| .gitignore | ||
| .mailmap | ||
| CODE_OF_CONDUCT.md | ||
| CONTRIBUTING.md | ||
| LICENSE.TXT | ||
| README.md | ||
| SECURITY.md | ||
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