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| author | Tom de Vries <tdevries@suse.de> | 2020-09-11 07:13:25 +0200 |
|---|---|---|
| committer | Tom de Vries <tdevries@suse.de> | 2020-09-11 07:27:56 +0200 |
| commit | 5e044c673f8e7d473a2207cd3ba32910c4f5fc75 (patch) | |
| tree | 7264d8140c269edddc43d605a816501766715353 /gcc | |
| parent | 60e537a026c037d8f3e5678acd148f9e44b4fb9c (diff) | |
| download | gcc-5e044c673f8e7d473a2207cd3ba32910c4f5fc75.zip gcc-5e044c673f8e7d473a2207cd3ba32910c4f5fc75.tar.gz gcc-5e044c673f8e7d473a2207cd3ba32910c4f5fc75.tar.bz2 | |
[nvptx] Fix UB in nvptx_assemble_value
When nvptx_assemble_value is called with size == 16, this bitshift runs
into UB:
...
val &= ((unsigned HOST_WIDE_INT)2 << (size * BITS_PER_UNIT - 1)) - 1;
...
Fix this by checking the shift amount.
Tested on nvptx.
gcc/ChangeLog:
* config/nvptx/nvptx.c (nvptx_assemble_value): Fix undefined
behaviour.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/config/nvptx/nvptx.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/gcc/config/nvptx/nvptx.c b/gcc/config/nvptx/nvptx.c index 4fca0ed..0c590d8 100644 --- a/gcc/config/nvptx/nvptx.c +++ b/gcc/config/nvptx/nvptx.c @@ -2053,7 +2053,9 @@ nvptx_assemble_value (unsigned HOST_WIDE_INT val, unsigned size) bool negative_p = val & (HOST_WIDE_INT_1U << (HOST_BITS_PER_WIDE_INT - 1)); - val &= ((unsigned HOST_WIDE_INT)2 << (size * BITS_PER_UNIT - 1)) - 1; + /* Avoid undefined behaviour. */ + if (size * BITS_PER_UNIT < HOST_BITS_PER_WIDE_INT) + val &= (HOST_WIDE_INT_1U << (size * BITS_PER_UNIT)) - 1; for (unsigned part = 0; size; size -= part) { |