[compiler-rt] a4e8f7f - [builtins] Improve compatibility with 16 bit targets

[Anton Korobeynikov via llvm-commits]

Author: Anatoly Trosinenko
Date: 2020-06-26T15:31:11+03:00
New Revision: a4e8f7fe3f38085c0fdd6e34e870f8e9c6c72861

URL: https://github.com/llvm/llvm-project/commit/a4e8f7fe3f38085c0fdd6e34e870f8e9c6c72861
DIFF: https://github.com/llvm/llvm-project/commit/a4e8f7fe3f38085c0fdd6e34e870f8e9c6c72861.diff

LOG: [builtins] Improve compatibility with 16 bit targets

Some parts of existing codebase assume the default `int` type to be (at least) 32 bit wide. On 16 bit targets such as MSP430 this may cause Undefined Behavior or results being defined but incorrect.

Differential Revision: https://reviews.llvm.org/D81408

Added: 
    

Modified: 
    compiler-rt/lib/builtins/floatdidf.c
    compiler-rt/lib/builtins/floatundidf.c
    compiler-rt/lib/builtins/fp_lib.h

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/builtins/floatdidf.c b/compiler-rt/lib/builtins/floatdidf.c
index 8f887314b9e1..b2d8f2b44b6d 100644
--- a/compiler-rt/lib/builtins/floatdidf.c
+++ b/compiler-rt/lib/builtins/floatdidf.c
@@ -87,7 +87,7 @@ COMPILER_RT_ABI double __floatdidf(di_int a) {
   }
   double_bits fb;
   fb.u.s.high = ((su_int)s & 0x80000000) |        // sign
-                ((e + 1023) << 20) |              // exponent
+                ((su_int)(e + 1023) << 20) |      // exponent
                 ((su_int)(a >> 32) & 0x000FFFFF); // mantissa-high
   fb.u.s.low = (su_int)a;                         // mantissa-low
   return fb.f;

diff  --git a/compiler-rt/lib/builtins/floatundidf.c b/compiler-rt/lib/builtins/floatundidf.c
index e7c6aae5ce38..4c445b118080 100644
--- a/compiler-rt/lib/builtins/floatundidf.c
+++ b/compiler-rt/lib/builtins/floatundidf.c
@@ -90,7 +90,7 @@ COMPILER_RT_ABI double __floatundidf(du_int a) {
     // a is now rounded to DBL_MANT_DIG bits
   }
   double_bits fb;
-  fb.u.s.high = ((e + 1023) << 20) |              // exponent
+  fb.u.s.high = ((su_int)(e + 1023) << 20) |      // exponent
                 ((su_int)(a >> 32) & 0x000FFFFF); // mantissa-high
   fb.u.s.low = (su_int)a;                         // mantissa-low
   return fb.f;

diff  --git a/compiler-rt/lib/builtins/fp_lib.h b/compiler-rt/lib/builtins/fp_lib.h
index e6ba077d2313..bd1f180f499e 100644
--- a/compiler-rt/lib/builtins/fp_lib.h
+++ b/compiler-rt/lib/builtins/fp_lib.h
@@ -46,7 +46,7 @@ typedef float fp_t;
 #define REP_C UINT32_C
 #define significandBits 23
 
-static __inline int rep_clz(rep_t a) { return __builtin_clz(a); }
+static __inline int rep_clz(rep_t a) { return clzsi(a); }
 
 // 32x32 --> 64 bit multiply
 static __inline void wideMultiply(rep_t a, rep_t b, rep_t *hi, rep_t *lo) {