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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47652 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -234,3 +234,30 @@ down by 8 and truncate it. It's not pretty but it works. We need some register
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allocation magic to make the hack go away (e.g. putting additional constraints
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on the result of the movb).
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//===---------------------------------------------------------------------===//
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This function:
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double a(double b) {return (unsigned)b;}
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compiles to this code:
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_a:
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subq $8, %rsp
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cvttsd2siq %xmm0, %rax
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movl $4294967295, %ecx
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andq %rcx, %rax
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cvtsi2sdq %rax, %xmm0
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addq $8, %rsp
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ret
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note the dead rsp adjustments. Also, there is surely a better/shorter way
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to clear the top 32-bits of a 64-bit register than movl+andq. Testcase here:
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unsigned long long c(unsigned long long a) {return a&4294967295; }
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_c:
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movl $4294967295, %ecx
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movq %rdi, %rax
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andq %rcx, %rax
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ret
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//===---------------------------------------------------------------------===//
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