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PING: [PATCH] Fix PRs c/52283/37985
- From: Christian Bruel <christian dot bruel at st dot com>
- To: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, "manu at gcc dot gnu dot org" <manu at gcc dot gnu dot org>
- Date: Wed, 18 Apr 2012 10:29:21 +0200
- Subject: PING: [PATCH] Fix PRs c/52283/37985
http://gcc.gnu.org/ml/gcc-patches/2012-04/msg00191.html
and discussed in
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52283
I would like to close the associated PRs to fix a few discrepancies with
the folding of constant expressions warnings.
Original patch from Manu was slightly modified to reflect the new
warn_if_unused_value location (moved from stmt.c to c-familly/c-common.c).
Is it OK for trunk, bootstrapped and regtested on x86
Many Thanks
Christian
gcc/testsuite/ChangeLog
2010-02-15 Christian Bruel <christian.bruel@st.com>
* gcc.dg/case-const-1.c: Test constant expression.
* gcc.dg/case-const-2.c: Likewise.
* gcc.dg/case-const-3.c: Likewise.
gcc/ChangeLog
2012-03-29 Manuel López-Ibáñez <manu@gcc.gnu.org>
PR c/52283
* c-familly/c-common.c (warn_if_unused_value): Skip NOP_EXPR.
* convert.c (convert_to_integer): Don't set TREE_NO_WARNING.
Index: gcc/c-family/c-common.c
===================================================================
--- gcc/c-family/c-common.c (revision 186524)
+++ gcc/c-family/c-common.c (working copy)
@@ -1692,6 +1692,7 @@
case SAVE_EXPR:
case NON_LVALUE_EXPR:
+ case NOP_EXPR:
exp = TREE_OPERAND (exp, 0);
goto restart;
Index: gcc/convert.c
===================================================================
--- gcc/convert.c (revision 186524)
+++ gcc/convert.c (working copy)
@@ -537,7 +537,6 @@
else if (outprec >= inprec)
{
enum tree_code code;
- tree tem;
/* If the precision of the EXPR's type is K bits and the
destination mode has more bits, and the sign is changing,
@@ -555,13 +554,7 @@
else
code = NOP_EXPR;
- tem = fold_unary (code, type, expr);
- if (tem)
- return tem;
-
- tem = build1 (code, type, expr);
- TREE_NO_WARNING (tem) = 1;
- return tem;
+ return fold_build1 (code, type, expr);
}
/* If TYPE is an enumeral type or a type with a precision less
Index: gcc/testsuite/gcc.dg/pr37985.c
===================================================================
--- gcc/testsuite/gcc.dg/pr37985.c (revision 0)
+++ gcc/testsuite/gcc.dg/pr37985.c (revision 0)
@@ -0,0 +1,8 @@
+/* PR c37985 */
+/* { dg-do compile } */
+/* { dg-options " -Wall -Wextra " } */
+unsigned char foo(unsigned char a)
+{
+ a >> 2; /* { dg-warning "no effect" } */
+ return a;
+}
Index: gcc/testsuite/gcc.dg/case-const-1.c
===================================================================
--- gcc/testsuite/gcc.dg/case-const-1.c (revision 186524)
+++ gcc/testsuite/gcc.dg/case-const-1.c (working copy)
@@ -1,9 +1,11 @@
/* Test for case labels not integer constant expressions but folding
- to integer constants (used in Linux kernel, PR 39613). */
+ to integer constants (used in Linux kernel, PR 39613, 52283). */
/* { dg-do compile } */
/* { dg-options "" } */
extern int i;
+extern unsigned int u;
+
void
f (int c)
{
@@ -13,3 +15,13 @@
;
}
}
+
+void
+b (int c)
+{
+ switch (c)
+ {
+ case (int) (2 | ((4 < 8) ? 8 : u)):
+ ;
+ }
+}
Index: gcc/testsuite/gcc.dg/case-const-2.c
===================================================================
--- gcc/testsuite/gcc.dg/case-const-2.c (revision 186524)
+++ gcc/testsuite/gcc.dg/case-const-2.c (working copy)
@@ -1,9 +1,11 @@
/* Test for case labels not integer constant expressions but folding
- to integer constants (used in Linux kernel, PR 39613). */
+ to integer constants (used in Linux kernel, PR 39613, 52283). */
/* { dg-do compile } */
/* { dg-options "-pedantic" } */
extern int i;
+extern unsigned int u;
+
void
f (int c)
{
@@ -13,3 +15,14 @@
;
}
}
+
+void
+b (int c)
+{
+ switch (c)
+ {
+ case (int) (2 | ((4 < 8) ? 8 : u)): /* { dg-warning "case label is not an integer constant expression" } */
+ ;
+ }
+}
+
Index: gcc/testsuite/gcc.dg/case-const-3.c
===================================================================
--- gcc/testsuite/gcc.dg/case-const-3.c (revision 186524)
+++ gcc/testsuite/gcc.dg/case-const-3.c (working copy)
@@ -1,9 +1,11 @@
/* Test for case labels not integer constant expressions but folding
- to integer constants (used in Linux kernel, PR 39613). */
+ to integer constants (used in Linux kernel, PR 39613, 52283, ). */
/* { dg-do compile } */
/* { dg-options "-pedantic-errors" } */
extern int i;
+extern unsigned int u;
+
void
f (int c)
{
@@ -13,3 +15,16 @@
;
}
}
+
+void
+b (int c)
+{
+ switch (c)
+ {
+ case (int) (2 | ((4 < 8) ? 8 : u)): /* { dg-error "case label is not an integer constant expression" } */
+ ;
+ }
+}
+
+
+