[PATCH] target/ppc: avoid int32 multiply overflow in int_helper.c

[Daniel Henrique Barboza]

Coverity is not thrilled about the multiply operations being done in
ger_rank8() and ger_rank2(), giving an error like the following:

Integer handling issues  (OVERFLOW_BEFORE_WIDEN)
    Potentially overflowing expression "sextract32(a, 4 * i, 4) *
sextract32(b, 4 * i, 4)" with type "int" (32 bits, signed) is evaluated
using 32-bit arithmetic, and then used in a context that expects an
expression of type "int64_t" (64 bits, signed).

Fix both instances where this occur by adding an int64_t cast in the
first operand, forcing the result to be 64 bit.

Fixes: Coverity CID 1489444, 1489443
Fixes: 345531533f26 ("target/ppc: Implemented xvi*ger* instructions")
Cc: Lucas Mateus Castro (alqotel) <lucas.araujo@eldorado.org.br>
Cc: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
 target/ppc/int_helper.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/target/ppc/int_helper.c b/target/ppc/int_helper.c
index 105b626d1b..eb65ab4d82 100644
--- a/target/ppc/int_helper.c
+++ b/target/ppc/int_helper.c
@@ -789,7 +789,7 @@ static int64_t ger_rank8(uint32_t a, uint32_t b, uint32_t 
mask)
     int64_t psum = 0;
     for (int i = 0; i < 8; i++, mask >>= 1) {
         if (mask & 1) {
-            psum += sextract32(a, 4 * i, 4) * sextract32(b, 4 * i, 4);
+            psum += (int64_t)sextract32(a, 4 * i, 4) * sextract32(b, 4 * i, 4);
         }
     }
     return psum;
@@ -811,7 +811,8 @@ static int64_t ger_rank2(uint32_t a, uint32_t b, uint32_t 
mask)
     int64_t psum = 0;
     for (int i = 0; i < 2; i++, mask >>= 1) {
         if (mask & 1) {
-            psum += sextract32(a, 16 * i, 16) * sextract32(b, 16 * i, 16);
+            psum += (int64_t)sextract32(a, 16 * i, 16) *
+                             sextract32(b, 16 * i, 16);
         }
     }
     return psum;
-- 
2.36.1