[Xen-changelog] [qemu-xen master] bitops: fix rol/ror when shift is zero

[patchbot@xxxxxxx]

commit ecce0369b864e3c505b89942cd8cc23a62a4386f
Author:     Nikunj A Dadhania <nikunj@xxxxxxxxxxxxxxxxxx>
AuthorDate: Sun Oct 30 08:44:55 2016 +0530
Commit:     David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
CommitDate: Tue Nov 15 10:05:50 2016 +1100

    bitops: fix rol/ror when shift is zero
    
    All the variants for rol/ror have a bug in case where the shift == 0.
    For example rol32, would generate:
    
        return (word << 0) | (word >> 32);
    
    Which though works, would be flagged as a runtime error on clang's
    sanitizer.
    
    Suggested-by: Richard Henderson <rth@xxxxxxxxxxx>
    Signed-off-by: Nikunj A Dadhania <nikunj@xxxxxxxxxxxxxxxxxx>
    Reviewed-by: Richard Henderson <rth@xxxxxxxxxxx>
    Signed-off-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
---
 include/qemu/bitops.h | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/qemu/bitops.h b/include/qemu/bitops.h
index 98fb005..1881284 100644
--- a/include/qemu/bitops.h
+++ b/include/qemu/bitops.h
@@ -218,7 +218,7 @@ static inline unsigned long hweight_long(unsigned long w)
  */
 static inline uint8_t rol8(uint8_t word, unsigned int shift)
 {
-    return (word << shift) | (word >> (8 - shift));
+    return (word << shift) | (word >> ((8 - shift) & 7));
 }
 
 /**
@@ -228,7 +228,7 @@ static inline uint8_t rol8(uint8_t word, unsigned int shift)
  */
 static inline uint8_t ror8(uint8_t word, unsigned int shift)
 {
-    return (word >> shift) | (word << (8 - shift));
+    return (word >> shift) | (word << ((8 - shift) & 7));
 }
 
 /**
@@ -238,7 +238,7 @@ static inline uint8_t ror8(uint8_t word, unsigned int shift)
  */
 static inline uint16_t rol16(uint16_t word, unsigned int shift)
 {
-    return (word << shift) | (word >> (16 - shift));
+    return (word << shift) | (word >> ((16 - shift) & 15));
 }
 
 /**
@@ -248,7 +248,7 @@ static inline uint16_t rol16(uint16_t word, unsigned int 
shift)
  */
 static inline uint16_t ror16(uint16_t word, unsigned int shift)
 {
-    return (word >> shift) | (word << (16 - shift));
+    return (word >> shift) | (word << ((16 - shift) & 15));
 }
 
 /**
@@ -258,7 +258,7 @@ static inline uint16_t ror16(uint16_t word, unsigned int 
shift)
  */
 static inline uint32_t rol32(uint32_t word, unsigned int shift)
 {
-    return (word << shift) | (word >> (32 - shift));
+    return (word << shift) | (word >> ((32 - shift) & 31));
 }
 
 /**
@@ -268,7 +268,7 @@ static inline uint32_t rol32(uint32_t word, unsigned int 
shift)
  */
 static inline uint32_t ror32(uint32_t word, unsigned int shift)
 {
-    return (word >> shift) | (word << (32 - shift));
+    return (word >> shift) | (word << ((32 - shift) & 31));
 }
 
 /**
@@ -278,7 +278,7 @@ static inline uint32_t ror32(uint32_t word, unsigned int 
shift)
  */
 static inline uint64_t rol64(uint64_t word, unsigned int shift)
 {
-    return (word << shift) | (word >> (64 - shift));
+    return (word << shift) | (word >> ((64 - shift) & 63));
 }
 
 /**
@@ -288,7 +288,7 @@ static inline uint64_t rol64(uint64_t word, unsigned int 
shift)
  */
 static inline uint64_t ror64(uint64_t word, unsigned int shift)
 {
-    return (word >> shift) | (word << (64 - shift));
+    return (word >> shift) | (word << ((64 - shift) & 63));
 }
 
 /**
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#master

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