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| author | Sylvain Henry <sylvain@haskus.fr> | 2020-07-08 14:05:24 +0200 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2020-07-09 09:50:01 -0400 |
| commit | 3656dff8259199d0dab2d1a1f1b887c252a9c1a3 (patch) | |
| tree | 0a8732f6969f865e50fce138ab4272a958b14bac | |
| parent | b7de4b960a1024adcd0bded6bd320a90979d7ab8 (diff) | |
| download | haskell-3656dff8259199d0dab2d1a1f1b887c252a9c1a3.tar.gz | |
LLVM: fix MO_S_Mul2 support (#18434)
The value indicating if the carry is useful wasn't taken into account.
| -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 |