c-common.c (c_common_truthvalue_conversion): Warn for multiplications in boolean context.

2016-10-24  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        * c-common.c (c_common_truthvalue_conversion): Warn for
        multiplications in boolean context.  Fix the quoting of '<<' and '<'
        in the shift warning.

gcc:
2016-10-24  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        * doc/invoke.text (Wint-in-bool-context): Update documentation.
        * value-prof.c (stringop_block_profile): Fix a warning.

testsuite:
2016-10-24  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        * c-c++-common/Wint-in-bool-context-3.c: New test.

From-SVN: r241490

gcc/ChangeLog

@@ -1,3 +1,8 @@
+2016-10-24  Bernd Edlinger  <bernd.edlinger@hotmail.de>
+
+	* doc/invoke.text (Wint-in-bool-context): Update documentation.
+	* value-prof.c (stringop_block_profile): Fix a warning.
+
 2016-10-24  Martin Sebor  <msebor@redhat.com>
 
 	PR middle-end/77735

gcc/c-family/ChangeLog

@@ -1,3 +1,9 @@
+2016-10-24  Bernd Edlinger  <bernd.edlinger@hotmail.de>
+
+	* c-common.c (c_common_truthvalue_conversion): Warn for
+	multiplications in boolean context.  Fix the quoting of '<<' and '<'
+	in the shift warning.
+
 2016-10-20  Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
 	* c-common.c (c_common_truthvalue_conversion): Fix the comment.

gcc/c-family/c-common.c

@@ -3327,6 +3327,11 @@ c_common_truthvalue_conversion (location_t location, tree expr)
 	return c_common_truthvalue_conversion (location,
 					       TREE_OPERAND (expr, 0));
 
+    case MULT_EXPR:
+      warning_at (EXPR_LOCATION (expr), OPT_Wint_in_bool_context,
+		  "%<*%> in boolean context, suggest %<&&%> instead");
+      break;
+
     case LSHIFT_EXPR:
       /* We will only warn on signed shifts here, because the majority of
 	 false positive warnings happen in code where unsigned arithmetic
@@ -3336,7 +3341,7 @@ c_common_truthvalue_conversion (location_t location, tree expr)
       if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
 	  && !TYPE_UNSIGNED (TREE_TYPE (expr)))
 	warning_at (EXPR_LOCATION (expr), OPT_Wint_in_bool_context,
-		    "<< in boolean context, did you mean '<' ?");
+		    "%<<<%> in boolean context, did you mean %<<%> ?");
       break;
 
     case COND_EXPR:

gcc/doc/invoke.texi

@@ -6169,8 +6169,9 @@ of the C++ standard.
 @opindex Wno-int-in-bool-context
 Warn for suspicious use of integer values where boolean values are expected,
 such as conditional expressions (?:) using non-boolean integer constants in
-boolean context, like @code{if (a <= b ? 2 : 3)}.  Or left shifting in
-boolean context, like @code{for (a = 0; 1 << a; a++);}.
+boolean context, like @code{if (a <= b ? 2 : 3)}.  Or left shifting of signed
+integers in boolean context, like @code{for (a = 0; 1 << a; a++);}.  Likewise
+for all kinds of multiplications regardless of the data type.
 This warning is enabled by @option{-Wall}.
 
 @item -Wno-int-to-pointer-cast

gcc/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2016-10-24  Bernd Edlinger  <bernd.edlinger@hotmail.de>
+
+	* c-c++-common/Wint-in-bool-context-3.c: New test.
+
 2016-10-24  Martin Sebor  <msebor@redhat.com>
 
 	PR middle-end/77735

gcc/testsuite/c-c++-common/Wint-in-bool-context-3.c

@@ -0,0 +1,15 @@
+/* { dg-options "-Wint-in-bool-context" } */
+/* { dg-do compile } */
+
+#define BITS_PER_UNIT 8
+
+int foo (int count)
+{
+  int alignment;
+ 
+  alignment = 1;
+  while (!(count & alignment)
+         && (alignment * 2 * BITS_PER_UNIT)) /* { dg-warning "boolean context" } */
+    alignment <<= 1;
+  return alignment * BITS_PER_UNIT;
+}

gcc/value-prof.c

@@ -1878,12 +1878,12 @@ stringop_block_profile (gimple *stmt, unsigned int *expected_align,
   else
     {
       gcov_type count;
-      int alignment;
+      unsigned int alignment;
 
       count = histogram->hvalue.counters[0];
       alignment = 1;
       while (!(count & alignment)
-	     && (alignment * 2 * BITS_PER_UNIT))
+	     && (alignment <= UINT_MAX / 2 / BITS_PER_UNIT))
 	alignment <<= 1;
       *expected_align = alignment * BITS_PER_UNIT;
       gimple_remove_histogram_value (cfun, stmt, histogram);