[PATCH] phiopt: factor could move a trapping statement across other trapping statements [PR117235]

[Andrew Pinski]

After r15-4503-g8d6d6d537fdc75, phiopt could move a trapping statement
across another trapping statement causing the order to be incorrect (might 
happen
with non-call exceptions).
To prevent this, a trapping statement has to be at the end of the basic block
to be allowed to be factored. This adds that check.

Bootstrapped and tested on x86_64-linux-gnu.

        PR tree-optimization/117235

gcc/ChangeLog:

        * tree-ssa-phiopt.cc (is_factor_profitable): Return false
        when a trapping statement is not the last statement of the
        basic block.

gcc/testsuite/ChangeLog:

        * gcc.dg/tree-ssa/factor_op_phi-5.c: New test.

Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
---
 .../gcc.dg/tree-ssa/factor_op_phi-5.c         | 24 +++++++++++++++++++
 gcc/tree-ssa-phiopt.cc                        |  6 +++++
 2 files changed, 30 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/factor_op_phi-5.c

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/factor_op_phi-5.c 
b/gcc/testsuite/gcc.dg/tree-ssa/factor_op_phi-5.c
new file mode 100644
index 00000000000..ad4338f3c08
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/factor_op_phi-5.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -ftrapping-math -fdump-tree-phiopt1-details" } */
+
+/* PR tree-optimization/117235 */
+
+/* The convert between int to float should not be factored as the statement
+   could be moved across another trapping statement.  */
+int f(int a, float b, float c, float d, int x, int y)
+{
+    float e;
+    float t;
+    if (a)
+    {
+        e = x;
+        t = c/d;
+    } else
+    {
+        e = y;
+        t = d/c;
+    }
+    return e + t;
+}
+
+/* { dg-final { scan-tree-dump-not "changed to factor operation out from " 
"phiopt1" } } */
diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
index 38cc8506d1f..6a89f57a41a 100644
--- a/gcc/tree-ssa-phiopt.cc
+++ b/gcc/tree-ssa-phiopt.cc
@@ -249,6 +249,12 @@ is_factor_profitable (gimple *def_stmt, basic_block merge, 
tree arg)
   if (gsi_end_p (gsi))
     return true;
 
+  /* If the defining statement could trap, then it is never
+     profitable to factor out the statement if not at the end
+     of the bb.  */
+  if (gimple_could_trap_p (def_stmt))
+    return false;
+
   /* Check if the uses of arg is dominated by merge block, this is a quick and
      rough estimate if arg is still alive at the merge bb.  */
   /* FIXME: extend to a more complete live range detection.  */
-- 
2.43.0