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author | Dan Gohman <gohman@apple.com> | 2010-06-03 20:21:33 +0000 |
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committer | Dan Gohman <gohman@apple.com> | 2010-06-03 20:21:33 +0000 |
commit | 400f75cb5ed39ab4f071f78f6a26beefbc8a46f0 (patch) | |
tree | 03b34bf45cb5dc8bc25cf7aba2987e2ec447b973 | |
parent | 3844173f6e5c2d3e309d71d8980e25cca1b9305d (diff) | |
download | llvm-400f75cb5ed39ab4f071f78f6a26beefbc8a46f0.tar.gz llvm-400f75cb5ed39ab4f071f78f6a26beefbc8a46f0.tar.bz2 llvm-400f75cb5ed39ab4f071f78f6a26beefbc8a46f0.tar.xz |
Fix SimplifyDemandedBits' AssertZext logic to demand all the bits. It
needs to demand the high bits because it's asserting that they're zero.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105406 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r-- | lib/CodeGen/SelectionDAG/TargetLowering.cpp | 12 | ||||
-rw-r--r-- | test/CodeGen/X86/promote-assert-zext.ll | 22 |
2 files changed, 30 insertions, 4 deletions
diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp index 44a80d3362..1cca100d56 100644 --- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp +++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp @@ -1498,13 +1498,17 @@ bool TargetLowering::SimplifyDemandedBits(SDValue Op, break; } case ISD::AssertZext: { - EVT VT = cast<VTSDNode>(Op.getOperand(1))->getVT(); - APInt InMask = APInt::getLowBitsSet(BitWidth, - VT.getSizeInBits()); - if (SimplifyDemandedBits(Op.getOperand(0), InMask & NewMask, + // Demand all the bits of the input that are demanded in the output. + // The low bits are obvious; the high bits are demanded because we're + // asserting that they're zero here. + if (SimplifyDemandedBits(Op.getOperand(0), NewMask, KnownZero, KnownOne, TLO, Depth+1)) return true; assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + + EVT VT = cast<VTSDNode>(Op.getOperand(1))->getVT(); + APInt InMask = APInt::getLowBitsSet(BitWidth, + VT.getSizeInBits()); KnownZero |= ~InMask & NewMask; break; } diff --git a/test/CodeGen/X86/promote-assert-zext.ll b/test/CodeGen/X86/promote-assert-zext.ll new file mode 100644 index 0000000000..b582806c96 --- /dev/null +++ b/test/CodeGen/X86/promote-assert-zext.ll @@ -0,0 +1,22 @@ +; RUN: llc < %s | FileCheck %s +; rdar://8051990 + +target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64" +target triple = "x86_64-apple-darwin11" + +; ISel doesn't yet know how to eliminate this extra zero-extend. But until +; it knows how to do so safely, it shouldn;t eliminate it. +; CHECK: movzbl (%rdi), %eax +; CHECK: movzwl %ax, %eax + +define i64 @_ZL5matchPKtPKhiR9MatchData(i8* %tmp13) nounwind { +entry: + %tmp14 = load i8* %tmp13, align 1 + %tmp17 = zext i8 %tmp14 to i16 + br label %bb341 + +bb341: + %tmp18 = add i16 %tmp17, -1 + %tmp23 = sext i16 %tmp18 to i64 + ret i64 %tmp23 +} |