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| author | segher <segher@138bc75d-0d04-0410-961f-82ee72b054a4> | 2016-11-23 23:30:38 +0000 |
|---|---|---|
| committer | segher <segher@138bc75d-0d04-0410-961f-82ee72b054a4> | 2016-11-23 23:30:38 +0000 |
| commit | 74d925e95b7b84f4b86bd80b691b28b73db3143f (patch) | |
| tree | 4f7438022bdf1a4e4449696b64295c5916e59252 /gcc/combine.c | |
| parent | 7bdc34461d6e3258f275ed5193026acda729955d (diff) | |
| download | gcc-74d925e95b7b84f4b86bd80b691b28b73db3143f.tar.gz | |
combine: Query can_change_dest_mode before changing dest mode
As reported in https://gcc.gnu.org/ml/gcc-patches/2016-11/msg02388.html .
Changing the mode of a hard register can lead to problems, or at least
it can make worse code if the result will need reloads.
* combine.c (change_zero_ext): Only change the mode of a hard register
destination if can_change_dest_mode holds for that.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@242812 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index ae25ef35ed9..ce6cfde534d 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -11230,7 +11230,8 @@ change_zero_ext (rtx pat) else if (GET_CODE (x) == ZERO_EXTEND && SCALAR_INT_MODE_P (mode) && REG_P (XEXP (x, 0)) - && HARD_REGISTER_P (XEXP (x, 0))) + && HARD_REGISTER_P (XEXP (x, 0)) + && can_change_dest_mode (XEXP (x, 0), 0, mode)) { size = GET_MODE_PRECISION (GET_MODE (XEXP (x, 0))); x = gen_rtx_REG (mode, REGNO (XEXP (x, 0))); |