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Diffstat (limited to 'gitlab/issues_text/target_ppc/host_missing/accel_TCG/852')
| -rw-r--r-- | gitlab/issues_text/target_ppc/host_missing/accel_TCG/852 | 31 |
1 files changed, 0 insertions, 31 deletions
diff --git a/gitlab/issues_text/target_ppc/host_missing/accel_TCG/852 b/gitlab/issues_text/target_ppc/host_missing/accel_TCG/852 deleted file mode 100644 index af6879140..000000000 --- a/gitlab/issues_text/target_ppc/host_missing/accel_TCG/852 +++ /dev/null @@ -1,31 +0,0 @@ -ppc64le: possible SIMD issue casting double to int -Description of problem: -Working with numpy in a ppc64le VM, I ran into a strange double -to casting issue, specifically when casting an array of 1.0 values to 1 values. The numpy folks guided me to a small reproducible test case. - -The attached [convert.c](/uploads/2dd7936f4defccf816ffee7c7c002e77/convert.c) creates double and int arrays of length `1 <= n <= 16`. The double array is filled with the value 1.0, and both arrays are passed to a function that converts the value. - -With `-O2`, output is as expected (truncated here): - -``` -i = 1: 1 -i = 2: 1 1 -i = 3: 1 1 1 -i = 4: 1 1 1 1 -i = 5: 1 1 1 1 1 -i = 6: 1 1 1 1 1 1 -``` - -With `-O3`, all values that fit into blocks of four become zero: -``` -i = 1: 1 -i = 2: 1 1 -i = 3: 1 1 1 -i = 4: 0 0 0 0 -i = 5: 0 0 0 0 1 -i = 6: 0 0 0 0 1 1 -``` - -I tested this with executables compiled on a physical ppc64le host, where the issue is not reproducible. -Steps to reproduce: -1. `gcc -O2 -o convert convert.c && ./convert` -2. `gcc -O3 -o convert convert.c && ./convert` |