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| author | Richard Biener <rguenther@suse.de> | 2019-08-20 12:02:56 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2019-08-20 12:02:56 +0000 |
| commit | 3ed01d5408045d80a1efc42fadacfcfb98f14997 (patch) | |
| tree | 5a8134073d50509866bc11b02a3f768d98a2a994 /gcc/tree-ssa-sccvn.c | |
| parent | a53aa4da8add4e3adc6c38f70eb172d570865831 (diff) | |
| download | gcc-3ed01d5408045d80a1efc42fadacfcfb98f14997.zip gcc-3ed01d5408045d80a1efc42fadacfcfb98f14997.tar.gz gcc-3ed01d5408045d80a1efc42fadacfcfb98f14997.tar.bz2 | |
re PR tree-optimization/37242 (missed FRE opportunity because of signedness of addition)
2019-08-20 Richard Biener <rguenther@suse.de>
PR tree-optimization/37242
* tree-ssa-sccvn.c (visit_nary_op): Also CSE (T)(a + b)
to (T)a + (T)b if we know that a + b does not overflow.
* gcc.dg/tree-ssa/ssa-fre-80.c: New testcase.
From-SVN: r274746
Diffstat (limited to 'gcc/tree-ssa-sccvn.c')
| -rw-r--r-- | gcc/tree-ssa-sccvn.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c index eb7e4be..76cad43 100644 --- a/gcc/tree-ssa-sccvn.c +++ b/gcc/tree-ssa-sccvn.c @@ -4312,8 +4312,12 @@ visit_nary_op (tree lhs, gassign *stmt) operation. */ if (INTEGRAL_TYPE_P (type) && TREE_CODE (rhs1) == SSA_NAME - /* We only handle sign-changes or zero-extension -> & mask. */ - && ((TYPE_UNSIGNED (TREE_TYPE (rhs1)) + /* We only handle sign-changes, zero-extension -> & mask or + sign-extension if we know the inner operation doesn't + overflow. */ + && (((TYPE_UNSIGNED (TREE_TYPE (rhs1)) + || (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) + && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (rhs1)))) && TYPE_PRECISION (type) > TYPE_PRECISION (TREE_TYPE (rhs1))) || TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (rhs1)))) { @@ -4347,7 +4351,9 @@ visit_nary_op (tree lhs, gassign *stmt) { unsigned lhs_prec = TYPE_PRECISION (type); unsigned rhs_prec = TYPE_PRECISION (TREE_TYPE (rhs1)); - if (lhs_prec == rhs_prec) + if (lhs_prec == rhs_prec + || (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) + && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (rhs1)))) { gimple_match_op match_op (gimple_match_cond::UNCOND, NOP_EXPR, type, ops[0]); |