[gcc r13-2498] Handle > INF and < INF correctly in range-op-float.cc

[Aldy Hernandez <aldyh@gcc.gnu.org>]

https://gcc.gnu.org/g:f5dc9da0a97734ab68a4af34875640ed1ca0c7d1

commit r13-2498-gf5dc9da0a97734ab68a4af34875640ed1ca0c7d1
Author: Aldy Hernandez <aldyh@redhat.com>
Date:   Tue Sep 6 08:20:54 2022 +0200

    Handle > INF and < INF correctly in range-op-float.cc
    
    The gfortran.dg/minlocval*.f90 tests are generating conditionals past
    the infinities.  For example:
    
            if (x <= +Inf)
              foo (x);
            else
              bar (x);
    
    It seems to me that the only possible value for x on the false side is
    either NAN or undefined (for !HONOR_NANS).
    
    gcc/ChangeLog:
    
            * range-op-float.cc (build_le): Handle NANs and going past infinity.
            (build_lt): Same.
            (build_ge): Same.
            (build_gt): Same.
            (foperator_lt::op1_range): Avoid adjustments to range if build_*
            returned false.
            (foperator_lt::op2_range): Same.
            (foperator_le::op1_range): Same.
            (foperator_le::op2_range): Same.
            (foperator_gt::op1_range): Same.
            (foperator_gt::op2_range): Same.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.dg/tree-ssa/vrp-float-inf-1.c: New test.

Diff:
---
 gcc/range-op-float.cc                           | 99 +++++++++++++++++++------
 gcc/testsuite/gcc.dg/tree-ssa/vrp-float-inf-1.c | 15 ++++
 2 files changed, 90 insertions(+), 24 deletions(-)

diff --git a/gcc/range-op-float.cc b/gcc/range-op-float.cc
index 050f07a9867..5fbbaa1fb36 100644
--- a/gcc/range-op-float.cc
+++ b/gcc/range-op-float.cc
@@ -224,36 +224,79 @@ frange_drop_ninf (frange &r, tree type)
 
 // (X <= VAL) produces the range of [-INF, VAL].
 
-static void
+static bool
 build_le (frange &r, tree type, const REAL_VALUE_TYPE &val)
 {
+  if (real_isnan (&val))
+    {
+      r.set_undefined ();
+      return false;
+    }
   r.set (type, dconstninf, val);
+  return true;
 }
 
 // (X < VAL) produces the range of [-INF, VAL).
 
-static void
+static bool
 build_lt (frange &r, tree type, const REAL_VALUE_TYPE &val)
 {
+  if (real_isnan (&val))
+    {
+      r.set_undefined ();
+      return false;
+    }
+  // < -INF is outside the range.
+  if (real_isinf (&val, 1))
+    {
+      if (HONOR_NANS (type))
+	frange_set_nan (r, type);
+      else
+	r.set_undefined ();
+      return false;
+    }
   // Hijack LE because we only support closed intervals.
   build_le (r, type, val);
+  return true;
 }
 
 // (X >= VAL) produces the range of [VAL, +INF].
 
-static void
+static bool
 build_ge (frange &r, tree type, const REAL_VALUE_TYPE &val)
 {
+  if (real_isnan (&val))
+    {
+      r.set_undefined ();
+      return false;
+    }
   r.set (type, val, dconstinf);
+  return true;
 }
 
 // (X > VAL) produces the range of (VAL, +INF].
 
-static void
+static bool
 build_gt (frange &r, tree type, const REAL_VALUE_TYPE &val)
 {
+  if (real_isnan (&val))
+    {
+      r.set_undefined ();
+      return false;
+    }
+  // > +INF is outside the range.
+  if (real_isinf (&val, 0))
+    {
+      if (HONOR_NANS (type))
+	frange_set_nan (r, type);
+      else
+	r.set_undefined ();
+      return false;
+    }
+
   // Hijack GE because we only support closed intervals.
   build_ge (r, type, val);
+  return true;
 }
 
 
@@ -520,10 +563,12 @@ foperator_lt::op1_range (frange &r,
   switch (get_bool_state (r, lhs, type))
     {
     case BRS_TRUE:
-      build_lt (r, type, op2.upper_bound ());
-      r.set_nan (fp_prop::NO);
-      // x < y implies x is not +INF.
-      frange_drop_inf (r, type);
+      if (build_lt (r, type, op2.upper_bound ()))
+	{
+	  r.set_nan (fp_prop::NO);
+	  // x < y implies x is not +INF.
+	  frange_drop_inf (r, type);
+	}
       break;
 
     case BRS_FALSE:
@@ -546,10 +591,12 @@ foperator_lt::op2_range (frange &r,
   switch (get_bool_state (r, lhs, type))
     {
     case BRS_TRUE:
-      build_gt (r, type, op1.lower_bound ());
-      r.set_nan (fp_prop::NO);
-      // x < y implies y is not -INF.
-      frange_drop_ninf (r, type);
+      if (build_gt (r, type, op1.lower_bound ()))
+	{
+	  r.set_nan (fp_prop::NO);
+	  // x < y implies y is not -INF.
+	  frange_drop_ninf (r, type);
+	}
       break;
 
     case BRS_FALSE:
@@ -618,8 +665,8 @@ foperator_le::op1_range (frange &r,
   switch (get_bool_state (r, lhs, type))
     {
     case BRS_TRUE:
-      build_le (r, type, op2.upper_bound ());
-      r.set_nan (fp_prop::NO);
+      if (build_le (r, type, op2.upper_bound ()))
+	r.set_nan (fp_prop::NO);
       break;
 
     case BRS_FALSE:
@@ -642,8 +689,8 @@ foperator_le::op2_range (frange &r,
   switch (get_bool_state (r, lhs, type))
     {
     case BRS_TRUE:
-      build_ge (r, type, op1.lower_bound ());
-      r.set_nan (fp_prop::NO);
+      if (build_ge (r, type, op1.lower_bound ()))
+	r.set_nan (fp_prop::NO);
       break;
 
     case BRS_FALSE:
@@ -712,10 +759,12 @@ foperator_gt::op1_range (frange &r,
   switch (get_bool_state (r, lhs, type))
     {
     case BRS_TRUE:
-      build_gt (r, type, op2.lower_bound ());
-      r.set_nan (fp_prop::NO);
-      // x > y implies x is not -INF.
-      frange_drop_ninf (r, type);
+      if (build_gt (r, type, op2.lower_bound ()))
+	{
+	  r.set_nan (fp_prop::NO);
+	  // x > y implies x is not -INF.
+	  frange_drop_ninf (r, type);
+	}
       break;
 
     case BRS_FALSE:
@@ -738,10 +787,12 @@ foperator_gt::op2_range (frange &r,
   switch (get_bool_state (r, lhs, type))
     {
     case BRS_TRUE:
-      build_lt (r, type, op1.upper_bound ());
-      r.set_nan (fp_prop::NO);
-      // x > y implies y is not +INF.
-      frange_drop_inf (r, type);
+      if (build_lt (r, type, op1.upper_bound ()))
+	{
+	  r.set_nan (fp_prop::NO);
+	  // x > y implies y is not +INF.
+	  frange_drop_inf (r, type);
+	}
       break;
 
     case BRS_FALSE:
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/vrp-float-inf-1.c b/gcc/testsuite/gcc.dg/tree-ssa/vrp-float-inf-1.c
new file mode 100644
index 00000000000..1d21cce41e6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp-float-inf-1.c
@@ -0,0 +1,15 @@
+// { dg-do compile }
+// { dg-options "-O2 -fdump-tree-evrp-details" }
+
+void foo ();
+void bar (double);
+
+void funky(double f, double g)
+{
+  if (f <= __builtin_inf ())
+    foo ();
+  else
+    bar (f);
+}
+
+// { dg-final { scan-tree-dump-not " Inf,  Inf" "evrp" } }