forked from OSchip/llvm-project
Add different "cast constant value" for several possible types.
Note these are actually generated by Phis with constant operands. llvm-svn: 685
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@ -15,17 +15,24 @@ begin
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end
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end
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; A constant argument to a Phi produces a Cast instruction in the
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; A constant argument to a Phi produces a Cast instruction in the
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; corresponding predecessor basic block. This has little to do with
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; corresponding predecessor basic block. This checks a few things:
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; selection but the code is a bit weird.
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; -- phi arguments coming from the bottom of the same basic block
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; (they should not be forward substituted in the machine code!)
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; -- code generation for casts of various types
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; -- use of immediate fields for integral constants of different sizes
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; -- branch on a constant condition
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;
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;
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void "mergeConstants"(int * %x, int * %y)
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void "mergeConstants"(int * %x, int * %y)
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begin
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begin
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; <label>:0 ; [#uses=1]
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; <label>:0
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br label %Top
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br label %Top
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Top: ; [#uses=4]
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Top:
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phi int [ 0, %0 ], [ 1, %Top ], [ 2, %Next ] ; <int>:0 [#uses=0]
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phi int [ 0, %0 ], [ 1, %Top ], [ 524288, %Next ]
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phi float [ 0.0, %0 ], [ 1.0, %Top ], [ 2.0, %Next ]
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phi double [ 0.5, %0 ], [ 1.5, %Top ], [ 2.5, %Next ]
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phi bool [ true, %0 ], [ false,%Top ], [ true, %Next ]
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br bool true, label %Top, label %Next
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br bool true, label %Top, label %Next
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Next: ; [#uses=2]
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Next:
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br label %Top
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br label %Top
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end
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end
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@ -71,10 +78,12 @@ end
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; Test cases where an LLVM instruction requires no machine
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; Test cases where an LLVM instruction requires no machine
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; instructions (e.g., cast int* to long). But there are 2 cases:
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; instructions (e.g., cast int* to long). But there are 2 cases:
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; 1. If the result register has only a single use, the operand will be
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; 1. If the result register has only a single use and the use is in the
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; copy-propagated during instruction selection.
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; same basic block, the operand will be copy-propagated during
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; 2. If the result register has multiple uses, it cannot be copy
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; instruction selection.
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; propagated during instruction selection. It will generate a
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; 2. If the result register has multiple uses or is in a different
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; basic block, it cannot (or will not) be copy propagated during
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; instruction selection. It will generate a
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; copy instruction (add-with-0), but this copy should get coalesced
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; copy instruction (add-with-0), but this copy should get coalesced
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; away by the register allocator.
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; away by the register allocator.
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;
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;
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