[PATCH v2 3/3] math-emu: Use statement expressions to fix Wshift-count-overflow warning

From: Vincent Chen
Date: Mon May 27 2019 - 02:21:09 EST


To avoid "shift count >= width of type" warning, using statement
expressions to implement the conditional controlling before constant shift

The modification in op-2.h is taken from the glibc
commit 'sysdeps/unix/sysv/lin ("fe0b1e854ad32")'.

Signed-off-by: Vincent Chen <vincentc@xxxxxxxxxxxxx>
---
Changes in v2
- This is an new patch to fix Wshift-count-overflow warning

include/math-emu/op-2.h | 17 +++++++----------
include/math-emu/op-common.h | 11 ++++++-----
2 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/include/math-emu/op-2.h b/include/math-emu/op-2.h
index 13a374f..244522b 100644
--- a/include/math-emu/op-2.h
+++ b/include/math-emu/op-2.h
@@ -567,16 +567,13 @@
*/

#define _FP_FRAC_ASSEMBLE_2(r, X, rsize) \
- do { \
- if (rsize <= _FP_W_TYPE_SIZE) \
- r = X##_f0; \
- else \
- { \
- r = X##_f1; \
- r <<= _FP_W_TYPE_SIZE; \
- r += X##_f0; \
- } \
- } while (0)
+ (void) (((rsize) <= _FP_W_TYPE_SIZE) \
+ ? ({ (r) = X##_f0; }) \
+ : ({ \
+ (r) = X##_f1; \
+ (r) <<= _FP_W_TYPE_SIZE; \
+ (r) += X##_f0; \
+ }))

#define _FP_FRAC_DISASSEMBLE_2(X, r, rsize) \
do { \
diff --git a/include/math-emu/op-common.h b/include/math-emu/op-common.h
index 6bdf8c6..f37d128 100644
--- a/include/math-emu/op-common.h
+++ b/include/math-emu/op-common.h
@@ -795,11 +795,12 @@
ur_ = (unsigned rtype) -r; \
else \
ur_ = (unsigned rtype) r; \
- if (rsize <= _FP_W_TYPE_SIZE) \
- __FP_CLZ(X##_e, ur_); \
- else \
- __FP_CLZ_2(X##_e, (_FP_W_TYPE)(ur_ >> _FP_W_TYPE_SIZE), \
- (_FP_W_TYPE)ur_); \
+ (void) (((rsize) <= _FP_W_TYPE_SIZE) \
+ ? ({ __FP_CLZ(X##_e, ur_); }) \
+ : ({ \
+ __FP_CLZ_2(X##_e, (_FP_W_TYPE)(ur_ >> _FP_W_TYPE_SIZE), \
+ (_FP_W_TYPE)ur_); \
+ })); \
if (rsize < _FP_W_TYPE_SIZE) \
X##_e -= (_FP_W_TYPE_SIZE - rsize); \
X##_e = rsize - X##_e - 1; \
--
1.7.1