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llvm-mirror/test/CodeGen/X86/trunc-to-bool.ll
Duncan Sands 1d0b7dccf7 When promoting the result of fp_to_uint/fp_to_sint,
inform the optimizers that the result must be zero/
sign extended from the smaller type.  For example,
if a fp to unsigned i16 is promoted to fp to i32,
then we are allowed to assume that the extra 16 bits
are zero (because the result of fp to i16 is undefined
if the result does not fit in an i16).  This is
quite aggressive, but should help the optimizers
produce better code.  This requires correcting a
test which thought that fp_to_uint is some kind
of truncation, which it is not: in the testcase
(which does fp to i1), either the fp value converts
to 0 or 1 or the result is undefined, which is
quite different to truncation.

llvm-svn: 58991
2008-11-10 17:28:30 +00:00

52 lines
1.2 KiB
LLVM

; An integer truncation to i1 should be done with an and instruction to make
; sure only the LSBit survives. Test that this is the case both for a returned
; value and as the operand of a branch.
; RUN: llvm-as < %s | llc -march=x86 | grep {\\(and\\)\\|\\(test.*\\\$1\\)} | \
; RUN: count 5
define i1 @test1(i32 %X) zeroext {
%Y = trunc i32 %X to i1
ret i1 %Y
}
define i1 @test2(i32 %val, i32 %mask) {
entry:
%shifted = ashr i32 %val, %mask
%anded = and i32 %shifted, 1
%trunced = trunc i32 %anded to i1
br i1 %trunced, label %ret_true, label %ret_false
ret_true:
ret i1 true
ret_false:
ret i1 false
}
define i32 @test3(i8* %ptr) {
%val = load i8* %ptr
%tmp = trunc i8 %val to i1
br i1 %tmp, label %cond_true, label %cond_false
cond_true:
ret i32 21
cond_false:
ret i32 42
}
define i32 @test4(i8* %ptr) {
%tmp = ptrtoint i8* %ptr to i1
br i1 %tmp, label %cond_true, label %cond_false
cond_true:
ret i32 21
cond_false:
ret i32 42
}
define i32 @test6(double %d) {
%tmp = fptosi double %d to i1
br i1 %tmp, label %cond_true, label %cond_false
cond_true:
ret i32 21
cond_false:
ret i32 42
}