[llvm-commits] [llvm] r127766 - in /llvm/trunk: docs/LangRef.html include/llvm/Target/TargetLowering.h lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp lib/Target/X86/X86ISelLowering.cpp lib/Target/X86/X86ISelLowering.h test/CodeGen/X86/bool-zext.ll
Evan Cheng
evan.cheng at apple.com
Wed Mar 16 17:17:58 PDT 2011
Thanks. But I am not crazy about getTypeForExtendedInteger(). Can you name it better so it's clear it's used for argument passing and return values?
Evan
On Mar 16, 2011, at 3:20 PM, Cameron Zwarich wrote:
> Author: zwarich
> Date: Wed Mar 16 17:20:18 2011
> New Revision: 127766
>
> URL: http://llvm.org/viewvc/llvm-project?rev=127766&view=rev
> Log:
> The x86-64 ABI says that a bool is only guaranteed to be sign-extended to a byte
> rather than an int. Thankfully, this only causes LLVM to miss optimizations, not
> generate incorrect code.
>
> This just fixes the zext at the return. We still insert an i32 ZextAssert when
> reading a function's arguments, but it is followed by a truncate and another i8
> ZextAssert so it is not optimized.
>
> Modified:
> llvm/trunk/docs/LangRef.html
> llvm/trunk/include/llvm/Target/TargetLowering.h
> llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
> llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
> llvm/trunk/lib/Target/X86/X86ISelLowering.h
> llvm/trunk/test/CodeGen/X86/bool-zext.ll
>
> Modified: llvm/trunk/docs/LangRef.html
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/LangRef.html?rev=127766&r1=127765&r2=127766&view=diff
> ==============================================================================
> --- llvm/trunk/docs/LangRef.html (original)
> +++ llvm/trunk/docs/LangRef.html Wed Mar 16 17:20:18 2011
> @@ -1017,8 +1017,9 @@
> <dl>
> <dt><tt><b>zeroext</b></tt></dt>
> <dd>This indicates to the code generator that the parameter or return value
> - should be zero-extended to a 32-bit value by the caller (for a parameter)
> - or the callee (for a return value).</dd>
> + should be zero-extended to the extent required by the target's ABI (which
> + is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
> + parameter) or the callee (for a return value).</dd>
>
> <dt><tt><b>signext</b></tt></dt>
> <dd>This indicates to the code generator that the parameter or return value
>
> Modified: llvm/trunk/include/llvm/Target/TargetLowering.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetLowering.h?rev=127766&r1=127765&r2=127766&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/Target/TargetLowering.h (original)
> +++ llvm/trunk/include/llvm/Target/TargetLowering.h Wed Mar 16 17:20:18 2011
> @@ -1287,6 +1287,17 @@
> return false;
> }
>
> + /// getTypeForExtendedInteger - Return the type that should be used to zero or
> + /// sign extend a zeroext/signext integer argument or return value.
> + /// FIXME: Most C calling convention requires the return type to be promoted,
> + /// but this is not true all the time, e.g. i1 on x86-64. It is also not
> + /// necessary for non-C calling conventions. The frontend should handle this
> + /// and include all of the necessary information.
> + virtual MVT
> + getTypeForExtendedInteger(EVT VT, ISD::NodeType ExtendKind) const {
> + return MVT::i32;
> + }
> +
> /// LowerOperationWrapper - This callback is invoked by the type legalizer
> /// to legalize nodes with an illegal operand type but legal result types.
> /// It replaces the LowerOperation callback in the type Legalizer.
>
> Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp?rev=127766&r1=127765&r2=127766&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp (original)
> +++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp Wed Mar 16 17:20:18 2011
> @@ -1128,12 +1128,9 @@
> else if (F->paramHasAttr(0, Attribute::ZExt))
> ExtendKind = ISD::ZERO_EXTEND;
>
> - // FIXME: C calling convention requires the return type to be promoted
> - // to at least 32-bit. But this is not necessary for non-C calling
> - // conventions. The frontend should mark functions whose return values
> - // require promoting with signext or zeroext attributes.
> if (ExtendKind != ISD::ANY_EXTEND && VT.isInteger()) {
> - EVT MinVT = TLI.getRegisterType(*DAG.getContext(), MVT::i32);
> + MVT ReturnMVT = TLI.getTypeForExtendedInteger(VT, ExtendKind);
> + EVT MinVT = TLI.getRegisterType(*DAG.getContext(), ReturnMVT);
> if (VT.bitsLT(MinVT))
> VT = MinVT;
> }
>
> Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=127766&r1=127765&r2=127766&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Wed Mar 16 17:20:18 2011
> @@ -1448,6 +1448,15 @@
> return HasRet;
> }
>
> +MVT
> +X86TargetLowering::getTypeForExtendedInteger(EVT VT,
> + ISD::NodeType ExtendKind) const {
> + // TODO: Is this also valid on 32-bit?
> + if (Subtarget->is64Bit() && VT == MVT::i1 && ExtendKind == ISD::ZERO_EXTEND)
> + return MVT::i8;
> + return MVT::i32;
> +}
> +
> /// LowerCallResult - Lower the result values of a call into the
> /// appropriate copies out of appropriate physical registers.
> ///
>
> Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.h?rev=127766&r1=127765&r2=127766&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86ISelLowering.h (original)
> +++ llvm/trunk/lib/Target/X86/X86ISelLowering.h Wed Mar 16 17:20:18 2011
> @@ -843,6 +843,9 @@
>
> virtual bool isUsedByReturnOnly(SDNode *N) const;
>
> + virtual MVT
> + getTypeForExtendedInteger(EVT VT, ISD::NodeType ExtendKind) const;
> +
> virtual bool
> CanLowerReturn(CallingConv::ID CallConv, bool isVarArg,
> const SmallVectorImpl<ISD::OutputArg> &Outs,
>
> Modified: llvm/trunk/test/CodeGen/X86/bool-zext.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/bool-zext.ll?rev=127766&r1=127765&r2=127766&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/bool-zext.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/bool-zext.ll Wed Mar 16 17:20:18 2011
> @@ -6,7 +6,7 @@
> define void @bar1(i1 zeroext %v1) nounwind ssp {
> entry:
> %conv = zext i1 %v1 to i32
> - %call = tail call i32 (...)* @foo(i32 %conv) nounwind
> + %call = tail call i32 (...)* @foo1(i32 %conv) nounwind
> ret void
> }
>
> @@ -16,8 +16,20 @@
> define void @bar2(i8 zeroext %v1) nounwind ssp {
> entry:
> %conv = zext i8 %v1 to i32
> - %call = tail call i32 (...)* @foo(i32 %conv) nounwind
> + %call = tail call i32 (...)* @foo1(i32 %conv) nounwind
> ret void
> }
>
> -declare i32 @foo(...)
> +; CHECK: @bar3
> +; CHECK: callq
> +; CHECK-NOT: movzbl
> +; CHECK-NOT: and
> +; CHECK: ret
> +define zeroext i1 @bar3() nounwind ssp {
> +entry:
> + %call = call i1 @foo2() nounwind
> + ret i1 %call
> +}
> +
> +declare i32 @foo1(...)
> +declare zeroext i1 @foo2()
>
>
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