[PATCH 08/10] Fix g++.dg/ubsan/pr63956.C

[David Malcolm <dmalcolm@redhat.com>]

With the location patch, various errors in g++.dg/ubsan/pr63956.C
change:

     8  constexpr int
     9  fn1 (int a, int b)
    10  {
    11    if (b != 2)
    12      a <<= b;
    13    return a;
    14  }
    15
    16  constexpr int i1 = fn1 (5, 3);
    17  constexpr int i2 = fn1 (5, -2); // { dg-error "is negative" }

Here's the first error as printed by the status quo:
g++.dg/ubsan/pr63956.C:17:24:   in constexpr expansion of ‘fn1(5, -2)’
g++.dg/ubsan/pr63956.C:17:30: error: right operand of shift expression ‘(5 << -2)’ is negative
 constexpr int i2 = fn1 (5, -2); // { dg-error "is negative" }
                              ^

...and with the location patch:
g++.dg/ubsan/pr63956.C:17:24:   in constexpr expansion of ‘fn1(5, -2)’
g++.dg/ubsan/pr63956.C:12:11: error: right operand of shift expression ‘(5 << -2)’ is negative
     a <<= b;
           ^
I believe this is an improvement: we're now identifying both relevant
places, rather than just one, and clearly highlighting the exact
subexpression of interest.

Hence this patch updates the testcase to reflect the improved
location information.

gcc/testsuite/ChangeLog:
	* g++.dg/ubsan/pr63956.C: Update dg directives to reflect
	improved location information.
---
 gcc/testsuite/g++.dg/ubsan/pr63956.C | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/gcc/testsuite/g++.dg/ubsan/pr63956.C b/gcc/testsuite/g++.dg/ubsan/pr63956.C
index 185a719..b265631 100644
--- a/gcc/testsuite/g++.dg/ubsan/pr63956.C
+++ b/gcc/testsuite/g++.dg/ubsan/pr63956.C
@@ -10,15 +10,18 @@ fn1 (int a, int b)
 {
   if (b != 2)
     a <<= b;
+    // { dg-error "5 << -2.. is negative" "" { target *-*-* } 12 }
+    // { dg-error "is >= than the precision of the left operand" "" { target *-*-* } 12 }
+    // { dg-error "-2 << 4.. is negative" "" { target *-*-* } 12 }
   return a;
 }
 
 constexpr int i1 = fn1 (5, 3);
-constexpr int i2 = fn1 (5, -2); // { dg-error "is negative" }
-constexpr int i3 = fn1 (5, sizeof (int) * __CHAR_BIT__); // { dg-error "is >= than the precision of the left operand" }
-constexpr int i4 = fn1 (5, 256); // { dg-error "is >= than the precision of the left operand" }
+constexpr int i2 = fn1 (5, -2); // { dg-message "in constexpr expansion" }
+constexpr int i3 = fn1 (5, sizeof (int) * __CHAR_BIT__); // { dg-message "in constexpr expansion" }
+constexpr int i4 = fn1 (5, 256); // { dg-message "in constexpr expansion" }
 constexpr int i5 = fn1 (5, 2);
-constexpr int i6 = fn1 (-2, 4); // { dg-error "is negative" }
+constexpr int i6 = fn1 (-2, 4); // { dg-message "in constexpr expansion" }
 constexpr int i7 = fn1 (0, 2);
 
 SA (i1 == 40);
@@ -30,13 +33,16 @@ fn2 (int a, int b)
 {
   if (b != 2)
     a >>= b;
+    // { dg-error "4 >> -1.. is negative" "" { target *-*-* } 35 }
+    // { dg-error "is >= than the precision of the left operand" "" { target *-*-* } 35 }
+
   return a;
 }
 
 constexpr int j1 = fn2 (4, 1);
-constexpr int j2 = fn2 (4, -1); // { dg-error "is negative" }
-constexpr int j3 = fn2 (10, sizeof (int) * __CHAR_BIT__); // { dg-error "is >= than the precision of the left operand" }
-constexpr int j4 = fn2 (1, 256); // { dg-error "is >= than the precision of the left operand" }
+constexpr int j2 = fn2 (4, -1); // { dg-message "in constexpr expansion" }
+constexpr int j3 = fn2 (10, sizeof (int) * __CHAR_BIT__); // { dg-message "in constexpr expansion" }
+constexpr int j4 = fn2 (1, 256); // { dg-message "in constexpr expansion" }
 constexpr int j5 = fn2 (5, 2);
 constexpr int j6 = fn2 (-2, 4);
 constexpr int j7 = fn2 (0, 4);
@@ -49,12 +55,12 @@ constexpr int
 fn3 (int a, int b)
 {
   if (b != 2)
-    a = a / b;
+    a = a / b; // { dg-error "..7 / 0.. is not a constant expression" }
   return a;
 }
 
 constexpr int k1 = fn3 (8, 4);
-constexpr int k2 = fn3 (7, 0); // { dg-error "is not a constant expression" }
+constexpr int k2 = fn3 (7, 0); // { dg-message "in constexpr expansion" }
 constexpr int k3 = fn3 (INT_MIN, -1); // { dg-error "overflow in constant expression" }
 
 SA (k1 == 2);
@@ -63,12 +69,12 @@ constexpr float
 fn4 (float a, float b)
 {
   if (b != 2.0)
-    a = a / b;
+    a = a / b; // { dg-error "is not a constant expression" }
   return a;
 }
 
 constexpr float l1 = fn4 (5.0, 3.0);
-constexpr float l2 = fn4 (7.0, 0.0); // { dg-error "is not a constant expression" }
+constexpr float l2 = fn4 (7.0, 0.0); // { dg-message "in constexpr expansion" }
 
 constexpr int
 fn5 (const int *a, int b)
-- 
1.8.5.3