[dpdk-dev] [PATCH 06/22] app: fix volatile read for GCC >= 4.6

[Thomas Monjalon]

From: Ivan Boule <ivan.boule at 6wind.com>

When a memory address must be read, for instance a [mapped] PCI register,
the read value is assigned to a local variable that is not used after,
as for instance:
    x = *((uint8_t *) mem_addr);

Such instructions do not compile with gcc 4.6.
The fix consists in adding the "volatile" attribute to the accessed data type
and to not assign the read value:
    *((volatile uint8_t *) mem_addr);

Acked-by: Olivier Matz <olivier.matz at 6wind.com>
Signed-off-by: Ivan Boule <ivan.boule at 6wind.com>
---
 app/test/test_memory.c |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/app/test/test_memory.c b/app/test/test_memory.c
index 8a25eca..96d35d9 100644
--- a/app/test/test_memory.c
+++ b/app/test/test_memory.c
@@ -61,7 +61,6 @@ test_memory(void)
 	uint64_t s;
 	unsigned i, j;
 	const struct rte_memseg *mem;
-	volatile uint8_t x;
 
 	/*
 	 * dump the mapped memory: the python-expect script checks
@@ -83,8 +82,7 @@ test_memory(void)
 
 		/* check memory */
 		for (j = 0; j<mem[i].len; j++) {
-			x = *((uint8_t *) mem[i].addr + j);
-			RTE_SET_USED(x);
+			*((volatile uint8_t *) mem[i].addr + j);
 		}
 	}
 
-- 
1.7.2.5