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| author | rth <rth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2016-03-02 21:09:54 +0000 |
|---|---|---|
| committer | rth <rth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2016-03-02 21:09:54 +0000 |
| commit | 4fa2ff1ed3dc92d609a1b8d78f34a06b9eec250c (patch) | |
| tree | baae125ee96286848093048fcb31ae88608f9fe0 /gcc/simplify-rtx.c | |
| parent | dfb6d13960428024e961ec9c8dea91ec0e317fdd (diff) | |
| download | gcc-4fa2ff1ed3dc92d609a1b8d78f34a06b9eec250c.tar.gz | |
PR rtl-opt/67145
* simplify-rtx.c (simplify_plus_minus): Allow reassoc without
simplification when all args are positive non-fixed registers.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@233916 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/simplify-rtx.c')
| -rw-r--r-- | gcc/simplify-rtx.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c index 450fa8b0320..e1a0319c26f 100644 --- a/gcc/simplify-rtx.c +++ b/gcc/simplify-rtx.c @@ -4421,9 +4421,26 @@ simplify_plus_minus (enum rtx_code code, machine_mode mode, rtx op0, n_ops = i; } - /* If nothing changed, fail. */ + /* If nothing changed, check that rematerialization of rtl instructions + is still required. */ if (!canonicalized) - return NULL_RTX; + { + /* Perform rematerialization if only all operands are registers and + all operations are PLUS. */ + /* ??? Also disallow (non-global, non-frame) fixed registers to work + around rs6000 and how it uses the CA register. See PR67145. */ + for (i = 0; i < n_ops; i++) + if (ops[i].neg + || !REG_P (ops[i].op) + || (REGNO (ops[i].op) < FIRST_PSEUDO_REGISTER + && fixed_regs[REGNO (ops[i].op)] + && !global_regs[REGNO (ops[i].op)] + && ops[i].op != frame_pointer_rtx + && ops[i].op != arg_pointer_rtx + && ops[i].op != stack_pointer_rtx)) + return NULL_RTX; + goto gen_result; + } /* Create (minus -C X) instead of (neg (const (plus X C))). */ if (n_ops == 2 @@ -4465,6 +4482,7 @@ simplify_plus_minus (enum rtx_code code, machine_mode mode, rtx op0, } /* Now make the result by performing the requested operations. */ + gen_result: result = ops[0].op; for (i = 1; i < n_ops; i++) result = gen_rtx_fmt_ee (ops[i].neg ? MINUS : PLUS, |