Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC
Commits:
bfa6b70f by ARATA Mizuki at 2025-06-06T05:49:24-04:00
x86 NCG: Fix code generation of bswap64 on i386
Co-authored-by: sheaf
Fix #25601
- - - - -
5 changed files:
- compiler/GHC/CmmToAsm/X86/CodeGen.hs
- + testsuite/tests/cmm/should_run/T25601.hs
- + testsuite/tests/cmm/should_run/T25601.stdout
- + testsuite/tests/cmm/should_run/T25601a.cmm
- testsuite/tests/cmm/should_run/all.T
Changes:
=====================================
compiler/GHC/CmmToAsm/X86/CodeGen.hs
=====================================
@@ -6067,10 +6067,23 @@ genByteSwap width dst src = do
W64 | is32Bit -> do
let Reg64 dst_hi dst_lo = localReg64 dst
RegCode64 vcode rhi rlo <- iselExpr64 src
- return $ vcode `appOL`
- toOL [ MOV II32 (OpReg rlo) (OpReg dst_hi),
- MOV II32 (OpReg rhi) (OpReg dst_lo),
- BSWAP II32 dst_hi,
+ tmp <- getNewRegNat II32
+ -- Swap the low and high halves of the register.
+ --
+ -- NB: if dst_hi == rhi, we must make sure to preserve the contents
+ -- of rhi before writing to dst_hi (#25601).
+ let shuffle = if dst_hi == rhi && dst_lo == rlo then
+ toOL [ MOV II32 (OpReg rhi) (OpReg tmp),
+ MOV II32 (OpReg rlo) (OpReg dst_hi),
+ MOV II32 (OpReg tmp) (OpReg dst_lo) ]
+ else if dst_hi == rhi then
+ toOL [ MOV II32 (OpReg rhi) (OpReg dst_lo),
+ MOV II32 (OpReg rlo) (OpReg dst_hi) ]
+ else
+ toOL [ MOV II32 (OpReg rlo) (OpReg dst_hi),
+ MOV II32 (OpReg rhi) (OpReg dst_lo) ]
+ return $ vcode `appOL` shuffle `appOL`
+ toOL [ BSWAP II32 dst_hi,
BSWAP II32 dst_lo ]
W16 -> do
let dst_r = getLocalRegReg dst
=====================================
testsuite/tests/cmm/should_run/T25601.hs
=====================================
@@ -0,0 +1,22 @@
+{-# LANGUAGE UnboxedTuples #-}
+{-# LANGUAGE MagicHash #-}
+{-# LANGUAGE ForeignFunctionInterface #-}
+{-# LANGUAGE GHCForeignImportPrim #-}
+{-# LANGUAGE UnliftedFFITypes #-}
+
+import Numeric
+import GHC.Prim
+import GHC.Word
+import GHC.IO
+import GHC.Ptr
+import Data.List
+import qualified Data.ByteString as BS
+
+foreign import prim "test" c_test :: Addr# -> State# RealWorld -> (# State# RealWorld, Word64# #)
+
+main :: IO ()
+main = do
+ let bs = BS.pack $ take 100000 [ fromIntegral i | i <- [(1 :: Int) ..] ]
+ n <- BS.useAsCString bs $ \(Ptr addr) -> IO $ \s ->
+ case c_test addr s of (# s', n #) -> (# s', W64# n #)
+ print $ showHex n ""
=====================================
testsuite/tests/cmm/should_run/T25601.stdout
=====================================
@@ -0,0 +1 @@
+"f3f1ffffffffffff"
=====================================
testsuite/tests/cmm/should_run/T25601a.cmm
=====================================
@@ -0,0 +1,7 @@
+#include "Cmm.h"
+
+test ( W_ buffer ) {
+ bits64 ret;
+ (ret) = prim %bswap64(%neg(%zx64(bits16[buffer + (12 :: W_)])));
+ return (ret);
+}
=====================================
testsuite/tests/cmm/should_run/all.T
=====================================
@@ -47,3 +47,8 @@ test('AtomicFetch',
],
multi_compile_and_run,
['AtomicFetch', [('AtomicFetch_cmm.cmm', '')], ''])
+
+test('T25601',
+ [req_cmm],
+ multi_compile_and_run,
+ ['T25601', [('T25601a.cmm', '')], ''])
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/bfa6b70f27dc2ce7fc890ec71103c40f...
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/bfa6b70f27dc2ce7fc890ec71103c40f...
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