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| author | Jeff Law <law@redhat.com> | 2015-04-15 06:24:28 -0600 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 2015-04-15 06:24:28 -0600 |
| commit | 5141ed426365a752343b2a8961d7b578f255b769 (patch) | |
| tree | 1d0879dbbab7c2c5b15c92110904392c69270b07 /gcc | |
| parent | 366ee94b445fd959c7947e45d2cb9a2a4a0b4509 (diff) | |
| download | gcc-5141ed426365a752343b2a8961d7b578f255b769.zip gcc-5141ed426365a752343b2a8961d7b578f255b769.tar.gz gcc-5141ed426365a752343b2a8961d7b578f255b769.tar.bz2 | |
re PR rtl-optimization/42522 ((zero_extract:SI (mem:QI) ...) misoptimized)
PR rtl-optimization/42522
* cse.c (fold_rtx): Try to simplify a ZERO_EXTRACT or
SIGN_EXTRACT as a whole object rather than simplifying
its operand.
From-SVN: r222125
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/cse.c | 9 |
2 files changed, 16 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index f1a96f27..a0f2fe7 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2015-04-15 Jeff Law <law@redhat.com> + + PR rtl-optimization/42522 + * cse.c (fold_rtx): Try to simplify a ZERO_EXTRACT or + SIGN_EXTRACT as a whole object rather than simplifying + its operand. + 2015-04-15 Jakub Jelinek <jakub@redhat.com> PR ipa/65765 @@ -3150,6 +3150,15 @@ fold_rtx (rtx x, rtx_insn *insn) { case MEM: case SUBREG: + /* The first operand of a SIGN/ZERO_EXTRACT has a different meaning + than it would in other contexts. Basically its mode does not + signify the size of the object read. That information is carried + by size operand. If we happen to have a MEM of the appropriate + mode in our tables with a constant value we could simplify the + extraction incorrectly if we allowed substitution of that value + for the MEM. */ + case ZERO_EXTRACT: + case SIGN_EXTRACT: if ((new_rtx = equiv_constant (x)) != NULL_RTX) return new_rtx; return x; |