From 742b0c53bca30b7c1d88ebcf0c105edbecefb0bf Mon Sep 17 00:00:00 2001 From: Ben Gamari Date: Wed, 2 Feb 2022 14:43:53 -0500 Subject: primops: Fix documentation of setByteArray# Previously the documentation was subtly incorrect regarding the bounds of the operation. Fix this and add a test asserting that a zero-length operation is in fact a no-op. --- compiler/GHC/Builtin/primops.txt.pp | 2 +- testsuite/tests/codeGen/should_run/setByteArray.hs | 11 +++++++---- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/compiler/GHC/Builtin/primops.txt.pp b/compiler/GHC/Builtin/primops.txt.pp index 772371235e..10dc9af4dc 100644 --- a/compiler/GHC/Builtin/primops.txt.pp +++ b/compiler/GHC/Builtin/primops.txt.pp @@ -1848,7 +1848,7 @@ primop CopyAddrToByteArrayOp "copyAddrToByteArray#" GenPrimOp primop SetByteArrayOp "setByteArray#" GenPrimOp MutableByteArray# s -> Int# -> Int# -> Int# -> State# s -> State# s - {{\tt setByteArray# ba off len c} sets the byte range {\tt [off, off+len]} of + {{\tt setByteArray# ba off len c} sets the byte range {\tt [off, off+len)} of the {\tt MutableByteArray#} to the byte {\tt c}.} with has_side_effects = True diff --git a/testsuite/tests/codeGen/should_run/setByteArray.hs b/testsuite/tests/codeGen/should_run/setByteArray.hs index 099376cb4b..c9a1012ccd 100644 --- a/testsuite/tests/codeGen/should_run/setByteArray.hs +++ b/testsuite/tests/codeGen/should_run/setByteArray.hs @@ -12,12 +12,15 @@ main :: IO () main = do BA ba <- IO $ \s0 -> case newByteArray# 8# s0 of (# !s1, !mba #) -> - case setByteArray# mba 0# 8# 65# s1 of + case setByteArray# mba 0# 8# 65# s1 of -- ASCII 'A' !s2 -> - case setByteArray# mba 1# 6# 67# s2 of + case setByteArray# mba 1# 6# 67# s2 of -- ASCII 'B' !s3 -> - case unsafeFreezeByteArray# mba s3 of - (# s4, ba #) -> (# s4, BA ba #) + -- N.B. 0-length should be a no-op + case setByteArray# mba 2# 0# 68# s3 of -- ASCII 'C' + !s4 -> + case unsafeFreezeByteArray# mba s4 of + (# s5, ba #) -> (# s5, BA ba #) let f (I# i) = putStrLn [C# (indexCharArray# ba i)] mapM_ f [0..7] -- cgit v1.2.1