Many thanks to Richard Biener for approving the midde-end
patch that cleared the way for this one. This nvptx patch
defines the target hook TARGET_TRULY_NOOP_TRUNCATION to
false, indicating that integer truncations require explicit
instructions. nvptx.c already defines TARGET_MODES_TIEABLE_P
and TARGET_CAN_CHANGE_MODE_CLASS to false, and as (previously)
documented that may require TARGET_TRULY_NOOP_TRUNCATION to
be defined likewise.
This patch decreases the number of unexpected failures in
the testsuite by 10, and increases the number of expected
passes by 4, including these previous FAILs/ICEs:
gcc.c-torture/compile/opout.c
gcc.dg/torture/pr79125.c
gcc.dg/tree-ssa/pr92085-1.c
Unfortunately there is one testsuite failure that used to
pass gcc.target/nvptx/v2si-cvt.c, but this isn't an ICE or
incorrect code. As explained in this test, the scan-assembler
already isn't testing what it should. Given that there are
several (nvptx) patches pending review that affect code
generation of this example, and (perhaps) more on the way,
I propose letting this test FAIL for now until the dust
settles and it becomes clear what instruction(s) should be
generated (certainly not a cvt.u32.u32).
This patch has been tested on nvptx-none hosted on
x86_64-pc-linux-gnu with "make" and "make check" with
fewer ICEs and no wrong code regressions.
Ok for mainline?
2020-07-16 Roger Sayle <ro...@nextmovesoftware.com>
gcc/ChangeLog
* config/nvptx/nvptx.c (nvptx_truly_noop_truncation): Implement.
(TARGET_TRULY_NOOP_TRUNCATION): Define.
Thanks in advance.
--
Roger Sayle
NextMove Software
Cambridge, UK
diff --git a/gcc/config/nvptx/nvptx.c b/gcc/config/nvptx/nvptx.c
index e3e84df..f5b5d8c 100644
--- a/gcc/config/nvptx/nvptx.c
+++ b/gcc/config/nvptx/nvptx.c
@@ -6450,6 +6450,14 @@ nvptx_can_change_mode_class (machine_mode, machine_mode,
reg_class_t)
return false;
}
+/* Implement TARGET_TRULY_NOOP_TRUNCATION. */
+
+static bool
+nvptx_truly_noop_truncation (poly_uint64, poly_uint64)
+{
+ return false;
+}
+
static GTY(()) tree nvptx_previous_fndecl;
static void
@@ -6599,6 +6607,9 @@ nvptx_set_current_function (tree fndecl)
#undef TARGET_CAN_CHANGE_MODE_CLASS
#define TARGET_CAN_CHANGE_MODE_CLASS nvptx_can_change_mode_class
+#undef TARGET_TRULY_NOOP_TRUNCATION
+#define TARGET_TRULY_NOOP_TRUNCATION nvptx_truly_noop_truncation
+
#undef TARGET_HAVE_SPECULATION_SAFE_VALUE
#define TARGET_HAVE_SPECULATION_SAFE_VALUE speculation_safe_value_not_needed
