llvm-mirror/test/Transforms/ConstProp/cast.ll
Eli Friedman 7ed3f1b26c Make uitofp and sitofp defined on overflow.
IEEE 754 defines the expected result on overflow. As far as I know,
hardware implementations (of f16), and compiler-rt (__floatuntisf)
correctly return +-Inf on overflow. And I can't think of any useful
transform that would take advantage of overflow being undefined here.

Differential Revision: https://reviews.llvm.org/D47807

llvm-svn: 334777
2018-06-14 22:58:48 +00:00

41 lines
1007 B
LLVM

; RUN: opt < %s -constprop -S | FileCheck %s
; Overflow on a float to int or int to float conversion is undefined (PR21130).
define i8 @overflow_fptosi() {
; CHECK-LABEL: @overflow_fptosi(
; CHECK-NEXT: ret i8 undef
;
%i = fptosi double 1.56e+02 to i8
ret i8 %i
}
define i8 @overflow_fptoui() {
; CHECK-LABEL: @overflow_fptoui(
; CHECK-NEXT: ret i8 undef
;
%i = fptoui double 2.56e+02 to i8
ret i8 %i
}
; The maximum float is approximately 2 ** 128 which is 3.4E38.
; The constant below is 4E38. Use a 130 bit integer to hold that
; number; 129-bits for the value + 1 bit for the sign.
define float @overflow_uitofp() {
; CHECK-LABEL: @overflow_uitofp(
; CHECK-NEXT: ret float 0x7FF0000000000000
;
%i = uitofp i130 400000000000000000000000000000000000000 to float
ret float %i
}
define float @overflow_sitofp() {
; CHECK-LABEL: @overflow_sitofp(
; CHECK-NEXT: ret float 0x7FF0000000000000
;
%i = sitofp i130 400000000000000000000000000000000000000 to float
ret float %i
}