diff options
| -rw-r--r-- | compiler/GHC/CmmToLlvm/CodeGen.hs | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/compiler/GHC/CmmToLlvm/CodeGen.hs b/compiler/GHC/CmmToLlvm/CodeGen.hs index 555e2de9e7..5581928a55 100644 --- a/compiler/GHC/CmmToLlvm/CodeGen.hs +++ b/compiler/GHC/CmmToLlvm/CodeGen.hs @@ -353,7 +353,7 @@ genCall (PrimTarget (MO_U_Mul2 w)) [dstH, dstL] [lhs, rhs] = runStmtsDecls $ do statement $ Store retL dstRegL statement $ Store retH dstRegH -genCall (PrimTarget (MO_S_Mul2 w)) [dstH, dstL] [lhs, rhs] = runStmtsDecls $ do +genCall (PrimTarget (MO_S_Mul2 w)) [dstC, dstH, dstL] [lhs, rhs] = runStmtsDecls $ do let width = widthToLlvmInt w bitWidth = widthInBits w width2x = LMInt (bitWidth * 2) @@ -373,10 +373,18 @@ genCall (PrimTarget (MO_S_Mul2 w)) [dstH, dstL] [lhs, rhs] = runStmtsDecls $ do retShifted <- doExprW width2x $ LlvmOp LM_MO_AShr retV widthLlvmLit -- And extract them into retH. retH <- doExprW width $ Cast LM_Trunc retShifted width + -- Check if the carry is useful by doing a full arithmetic right shift on + -- retL and comparing the result with retH + let widthLlvmLitm1 = LMLitVar $ LMIntLit (fromIntegral bitWidth - 1) width + retH' <- doExprW width $ LlvmOp LM_MO_AShr retL widthLlvmLitm1 + retC1 <- doExprW i1 $ Compare LM_CMP_Ne retH retH' -- Compare op returns a 1-bit value (i1) + retC <- doExprW width $ Cast LM_Zext retC1 width -- so we zero-extend it dstRegL <- getCmmRegW (CmmLocal dstL) dstRegH <- getCmmRegW (CmmLocal dstH) + dstRegC <- getCmmRegW (CmmLocal dstC) statement $ Store retL dstRegL statement $ Store retH dstRegH + statement $ Store retC dstRegC -- MO_U_QuotRem2 is another case we handle by widening the registers to double -- the width and use normal LLVM instructions (similarly to the MO_U_Mul2). The |