The heuristics for factoring out with a constant checks that the assignment
statement
is the last statement of the basic block but sometimes there is a predicate or
a nop statement
after the assignment. Rejecting this case does not make sense since both
predicates and nop
statements are removed and don't contribute any instructions. So we should skip
over them
when checking if the assignment statement was the last statement in the basic
block.
phi-opt-factor-1.c's f0 is such an example where it should catch it at phiopt1
(before predicates are removed)
and should happen in a similar way as f1 (which uses a temporary variable
rather than return).
Bootstrapped and tested on x86_64-linux-gnu.
PR tree-optimization/116699
gcc/ChangeLog:
* tree-ssa-phiopt.cc (factor_out_conditional_operation): Skip over
nop/predicates
for seeing the assignment is the last statement.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/phi-opt-factor-1.c: New test.
Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
---
.../gcc.dg/tree-ssa/phi-opt-factor-1.c | 26 +++++++++++++++++++
gcc/tree-ssa-phiopt.cc | 6 +++++
2 files changed, 32 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/phi-opt-factor-1.c
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-factor-1.c
b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-factor-1.c
new file mode 100644
index 00000000000..12b846b9337
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-factor-1.c
@@ -0,0 +1,26 @@
+/* { dg-options "-O2 -fdump-tree-phiopt" } */
+
+/* PR tree-optimization/116699
+ Make sure the return PREDICT has no factor in deciding
+ if we factor out the conversion. */
+
+short f0(int a, int b, int c)
+{
+ int t1 = 4;
+ if (c < t1) return (c > -1 ? c : -1);
+ return t1;
+}
+
+
+short f1(int a, int b, int c)
+{
+ int t1 = 4;
+ short t = t1;
+ if (c < t1) t = (c > -1 ? c : -1);
+ return t;
+}
+
+/* Both f1 and f0 should be optimized at phiopt1 to the same thing. */
+/* { dg-final { scan-tree-dump-times "MAX_EXPR " 2 "phiopt1" } } */
+/* { dg-final { scan-tree-dump-times "MIN_EXPR " 2 "phiopt1" } } */
+/* { dg-final { scan-tree-dump-not "if " "phiopt1" } } */
diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
index e5413e40572..7b12692237e 100644
--- a/gcc/tree-ssa-phiopt.cc
+++ b/gcc/tree-ssa-phiopt.cc
@@ -360,6 +360,12 @@ factor_out_conditional_operation (edge e0, edge e1, gphi
*phi,
}
gsi = gsi_for_stmt (arg0_def_stmt);
gsi_next_nondebug (&gsi);
+ /* Skip past nops and predicates. */
+ while (!gsi_end_p (gsi)
+ && (gimple_code (gsi_stmt (gsi)) == GIMPLE_NOP
+ || gimple_code (gsi_stmt (gsi)) == GIMPLE_PREDICT))
+ gsi_next_nondebug (&gsi);
+ /* Reject if the statement was not at the end of the block. */
if (!gsi_end_p (gsi))
return NULL;
}
--
2.43.0
