diff options
Diffstat (limited to 'compiler/nativeGen/RegAlloc/Linear/Main.hs')
| -rw-r--r-- | compiler/nativeGen/RegAlloc/Linear/Main.hs | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/compiler/nativeGen/RegAlloc/Linear/Main.hs b/compiler/nativeGen/RegAlloc/Linear/Main.hs index fc5b992603..fa71457808 100644 --- a/compiler/nativeGen/RegAlloc/Linear/Main.hs +++ b/compiler/nativeGen/RegAlloc/Linear/Main.hs @@ -116,7 +116,7 @@ import Instruction import Reg import BlockId -import OldCmm hiding (RegSet) +import Cmm hiding (RegSet) import Digraph import DynFlags @@ -743,12 +743,13 @@ allocateRegsAndSpill reading keep spills alloc (r:rs) Just (InMem slot) | reading -> doSpill (ReadMem slot) | otherwise -> doSpill WriteMem Nothing | reading -> - -- pprPanic "allocateRegsAndSpill: Cannot read from uninitialized register" (ppr r) - -- ToDo: This case should be a panic, but we - -- sometimes see an unreachable basic block which - -- triggers this because the register allocator - -- will start with an empty assignment. - doSpill WriteNew + pprPanic "allocateRegsAndSpill: Cannot read from uninitialized register" (ppr r) + -- NOTE: if the input to the NCG contains some + -- unreachable blocks with junk code, this panic + -- might be triggered. Make sure you only feed + -- sensible code into the NCG. In CmmPipeline we + -- call removeUnreachableBlocks at the end for this + -- reason. | otherwise -> doSpill WriteNew |