We can't yet represent the inverse of all conditions in rtl
(see g:865257c447cc50f5819e), triggering an ICE in the pass
that handles -mtrack-speculation. Since we don't expect these
insns to be optimised in any way, the easiest fix seemed to be
to add an insn that reverses the condition internally.
Tested on aarch64-linux-gnu. Also tested by making sure there
were no changes in asm output for fold-const.ii when compiled
with -O2 -mtrack-speculation. Committed.
Richard
2020-01-23 Richard Sandiford <richard.sandif...@arm.com>
gcc/
PR target/93341
* config/aarch64/aarch64.md (UNSPEC_SPECULATION_TRACKER_REV): New
unspec.
(speculation_tracker_rev): New pattern.
* config/aarch64/aarch64-speculation.cc (aarch64_do_track_speculation):
Use speculation_tracker_rev to track the inverse condition.
gcc/testsuite/
PR target/93341
* gcc.target/aarch64/pr93341.c: New test.
---
gcc/config/aarch64/aarch64-speculation.cc | 17 +++++------------
gcc/config/aarch64/aarch64.md | 15 +++++++++++++++
gcc/testsuite/gcc.target/aarch64/pr93341.c | 14 ++++++++++++++
3 files changed, 34 insertions(+), 12 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/aarch64/pr93341.c
diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index 55dde54b16a..4f5898185f5 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -262,6 +262,7 @@ (define_c_enum "unspec" [
UNSPEC_REV_SUBREG
UNSPEC_REINTERPRET
UNSPEC_SPECULATION_TRACKER
+ UNSPEC_SPECULATION_TRACKER_REV
UNSPEC_COPYSIGN
UNSPEC_TTEST ; Represent transaction test.
UNSPEC_UPDATE_FFR
@@ -7219,6 +7220,20 @@ (define_insn "speculation_tracker"
[(set_attr "type" "csel")]
)
+;; Like speculation_tracker, but track the inverse condition.
+(define_insn "speculation_tracker_rev"
+ [(set (reg:DI SPECULATION_TRACKER_REGNUM)
+ (unspec:DI [(reg:DI SPECULATION_TRACKER_REGNUM) (match_operand 0)]
+ UNSPEC_SPECULATION_TRACKER_REV))]
+ ""
+ {
+ operands[1] = gen_rtx_REG (DImode, SPECULATION_TRACKER_REGNUM);
+ output_asm_insn ("csel\\t%1, %1, xzr, %M0", operands);
+ return "";
+ }
+ [(set_attr "type" "csel")]
+)
+
;; BTI <target> instructions
(define_insn "bti_noarg"
[(unspec_volatile [(const_int 0)] UNSPECV_BTI_NOARG)]
diff --git a/gcc/config/aarch64/aarch64-speculation.cc
b/gcc/config/aarch64/aarch64-speculation.cc
index 98dcc11fb75..f490b64ae61 100644
--- a/gcc/config/aarch64/aarch64-speculation.cc
+++ b/gcc/config/aarch64/aarch64-speculation.cc
@@ -215,20 +215,13 @@ aarch64_do_track_speculation ()
&& REG_P (XEXP (cond, 0))
&& REGNO (XEXP (cond, 0)) == CC_REGNUM
&& XEXP (cond, 1) == const0_rtx);
- enum rtx_code inv_cond_code
- = reversed_comparison_code (cond, insn);
- /* We should be able to reverse all conditions. */
- gcc_assert (inv_cond_code != UNKNOWN);
- rtx inv_cond = gen_rtx_fmt_ee (inv_cond_code, GET_MODE (cond),
- copy_rtx (XEXP (cond, 0)),
- copy_rtx (XEXP (cond, 1)));
+ rtx branch_tracker = gen_speculation_tracker (copy_rtx (cond));
+ rtx fallthru_tracker = gen_speculation_tracker_rev (cond);
if (inverted)
- std::swap (cond, inv_cond);
+ std::swap (branch_tracker, fallthru_tracker);
- insert_insn_on_edge (gen_speculation_tracker (cond),
- BRANCH_EDGE (bb));
- insert_insn_on_edge (gen_speculation_tracker (inv_cond),
- FALLTHRU_EDGE (bb));
+ insert_insn_on_edge (branch_tracker, BRANCH_EDGE (bb));
+ insert_insn_on_edge (fallthru_tracker, FALLTHRU_EDGE (bb));
needs_tracking = true;
}
else if (GET_CODE (PATTERN (insn)) == RETURN)
diff --git a/gcc/testsuite/gcc.target/aarch64/pr93341.c
b/gcc/testsuite/gcc.target/aarch64/pr93341.c
new file mode 100644
index 00000000000..1efebeee21a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/pr93341.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-mtrack-speculation" } */
+
+int synths_ ( float * rc)
+{
+ float r1, r2;
+ int i;
+ for (i = 0; i < 128; ++i)
+ {
+ r2 = rc[i];
+ r1 = ((r2) <= (.99f) ? (r2) : (.99f));
+ rc[i] = ((r1) >= (-.99f) ? (r1) : (-.99f));
+ }
+}
