In the case of a NOP conversion (precisions of the 2 types are equal),
factoring out the conversion can be done even if int_fits_type_p returns
false and even when the conversion is defined by a statement inside the
conditional. Since it is a NOP conversion there is no zero/sign extending
happening which is why it is ok to be done here.

OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

gcc/ChangeLog:

        PR tree-optimization/104376
        PR tree-optimization/101541
        * tree-ssa-phiopt.cc (factor_out_conditional_operation):
        Allow nop conversions even if it is defined by a statement
        inside the conditional.

gcc/testsuite/ChangeLog:

        PR tree-optimization/101541
        * gcc.dg/tree-ssa/phi-opt-38.c: New test.
---
 gcc/testsuite/gcc.dg/tree-ssa/phi-opt-38.c | 44 ++++++++++++++++++++++
 gcc/tree-ssa-phiopt.cc                     |  8 +++-
 2 files changed, 50 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/phi-opt-38.c

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-38.c 
b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-38.c
new file mode 100644
index 00000000000..ca04d1619e6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-38.c
@@ -0,0 +1,44 @@
+/* { dg-options "-O2 -fdump-tree-phiopt" } */
+
+unsigned f0(int A)
+{
+//     A == 0? A : -A    same as -A
+  if (A == 0)  return A;
+  return -A;
+}
+
+unsigned f1(int A)
+{
+//     A != 0? A : -A    same as A
+  if (A != 0)  return A;
+  return -A;
+}
+unsigned f2(int A)
+{
+//     A >= 0? A : -A    same as abs (A)
+  if (A >= 0)  return A;
+  return -A;
+}
+unsigned f3(int A)
+{
+//     A > 0?  A : -A    same as abs (A)
+  if (A > 0)  return A;
+  return -A;
+}
+unsigned f4(int A)
+{
+//     A <= 0? A : -A    same as -abs (A)
+  if (A <= 0)  return A;
+  return -A;
+}
+unsigned f5(int A)
+{
+//     A < 0?  A : -A    same as -abs (A)
+  if (A < 0)  return A;
+  return -A;
+}
+
+/* f4 and f5 are not allowed to be optimized in early phi-opt. */
+/* { dg-final { scan-tree-dump-times "if" 2 "phiopt1" } } */
+/* { dg-final { scan-tree-dump-not "if" "phiopt2" } } */
+
diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
index 312a6f9082b..0ab8fad5898 100644
--- a/gcc/tree-ssa-phiopt.cc
+++ b/gcc/tree-ssa-phiopt.cc
@@ -310,7 +310,9 @@ factor_out_conditional_operation (edge e0, edge e1, gphi 
*phi,
        return NULL;
       /* If arg1 is an INTEGER_CST, fold it to new type.  */
       if (INTEGRAL_TYPE_P (TREE_TYPE (new_arg0))
-         && int_fits_type_p (arg1, TREE_TYPE (new_arg0)))
+         && (int_fits_type_p (arg1, TREE_TYPE (new_arg0))
+             || TYPE_PRECISION (TREE_TYPE (new_arg0))
+                 == TYPE_PRECISION (TREE_TYPE (arg1))))
        {
          if (gimple_assign_cast_p (arg0_def_stmt))
            {
@@ -323,7 +325,9 @@ factor_out_conditional_operation (edge e0, edge e1, gphi 
*phi,
                 its basic block, because then it is possible this
                 could enable further optimizations (minmax replacement
                 etc.).  See PR71016.  */
-             if (new_arg0 != gimple_cond_lhs (cond_stmt)
+             if (TYPE_PRECISION (TREE_TYPE (new_arg0))
+                   != TYPE_PRECISION (TREE_TYPE (arg1))
+                 && new_arg0 != gimple_cond_lhs (cond_stmt)
                  && new_arg0 != gimple_cond_rhs (cond_stmt)
                  && gimple_bb (arg0_def_stmt) == e0->src)
                {
-- 
2.34.1

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