1 // REQUIRES: x86-registered-target 2 // RUN: %clang -O1 -fvectorize -target x86_64-unknown-unknown -mllvm -vectorize-memory-check-threshold=8 -Rpass-analysis=loop-vectorize -emit-llvm -S %s -o - 2>&1 | FileCheck %s 3 4 // CHECK: {{.*}}:10:11: remark: loop not vectorized: cannot prove it is safe to reorder floating-point operations; allow reordering by specifying '#pragma clang loop vectorize(enable)' before the loop or by providing the compiler option '-ffast-math'. 5 6 double foo(int N) { 7 double v = 0.0; 8 9 for (int i = 0; i < N; i++) 10 v = v + 1.0; 11 12 return v; 13 } 14 15 // CHECK: {{.*}}:18:3: remark: loop not vectorized: cannot prove it is safe to reorder memory operations; allow reordering by specifying '#pragma clang loop vectorize(enable)' before the loop. If the arrays will always be independent specify '#pragma clang loop vectorize(assume_safety)' before the loop or provide the '__restrict__' qualifier with the independent array arguments. Erroneous results will occur if these options are incorrectly applied! 16 17 void foo2(int *dw, int *uw, int *A, int *B, int *C, int *D, int N) { 18 for (long i = 0; i < N; i++) { 19 dw[i] = A[i] + B[i - 1] + C[i - 2] + D[i - 3]; 20 uw[i] = A[i] + B[i + 1] + C[i + 2] + D[i + 3]; 21 } 22 } 23