[arm] Early split addvdi4
authorRichard Earnshaw <rearnsha@arm.com>
Fri, 18 Oct 2019 19:04:38 +0000 (19:04 +0000)
committerRichard Earnshaw <rearnsha@gcc.gnu.org>
Fri, 18 Oct 2019 19:04:38 +0000 (19:04 +0000)
commitfa62df0e600ef617bce549d64026c0e5cc817c31
tree56583c6d248e02eafd0d9dde04728a3aa05e74dd
parentdb962d0ad4501f2f673fc3fadd4ac572ef9a177e
[arm] Early split addvdi4

This patch adds early splitting for addvdi4; it's very similar to the
uaddvdi4 splitter, but the details are just different enough in
places, especially for the patterns that match the splitting, where we
have to compare against the non-widened version to detect if overflow
occurred.

I've also added a testcase to the testsuite for a couple of constants
that caught me out during the development of this patch.  They're
probably arm-specific values, but the test is generic enough that I've
included it for all targets.

[gcc]
* config/arm/arm.c (arm_select_cc_mode): Allow either the first
or second operand of the PLUS inside a DImode equality test to be
sign-extend when selecting CC_Vmode.
* config/arm/arm.md (addvdi4): Early-split the operation into SImode
instructions.
(addsi3_cin_vout_reg, addsi3_cin_vout_imm, addsi3_cin_vout_0): New
expand patterns.
(addsi3_cin_vout_reg_insn, addsi3_cin_vout_imm_insn): New patterns.
(addsi3_cin_vout_0): Likewise.
(adddi3_compareV): Delete.

[gcc/testsuite]
* gcc.dg/builtin-arith-overflow-3.c: New test.

From-SVN: r277186
gcc/ChangeLog
gcc/config/arm/arm.c
gcc/config/arm/arm.md
gcc/testsuite/ChangeLog
gcc/testsuite/gcc.dg/builtin-arith-overflow-3.c [new file with mode: 0644]