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llvm-mirror/test/CodeGen/PowerPC/change-no-infs.ll
Justin Lebar e3fb38059f [TM] Restore default TargetOptions in TargetMachine::resetTargetOptions.
Summary:
Previously if you had

 * a function with the fast-math-enabled attr, followed by
 * a function without the fast-math attr,

the second function would inherit the first function's fast-math-ness.

This means that mixing fast-math and non-fast-math functions in a module
was completely broken unless you explicitly annotated every
non-fast-math function with "unsafe-fp-math"="false".  This appears to
have been broken since r176986 (March 2013), when the resetTargetOptions
function was introduced.

This patch tests the correct behavior as best we can.  I don't think I
can test FPDenormalMode and NoTrappingFPMath, because they aren't used
in any backends during function lowering.  Surprisingly, I also can't
find any uses at all of LessPreciseFPMAD affecting generated code.

The NVPTX/fast-math.ll test changes are an expected result of fixing
this bug.  When FMA is disabled, we emit add as "add.rn.f32", which
prevents fma combining.  Before this patch, fast-math was enabled in all
functions following the one which explicitly enabled it on itself, so we
were emitting plain "add.f32" where we should have generated
"add.rn.f32".

Reviewers: mkuper

Subscribers: hfinkel, majnemer, jholewinski, nemanjai, llvm-commits

Differential Revision: https://reviews.llvm.org/D28507

llvm-svn: 291618
2017-01-10 23:43:04 +00:00

68 lines
2.0 KiB
LLVM

; Check that we can enable/disable NoInfsFPMath and NoNaNsInFPMath via function
; attributes. An attribute on one function should not magically apply to the
; next one.
; RUN: llc < %s -mtriple=powerpc64-unknown-unknown -mcpu=pwr7 -mattr=-vsx \
; RUN: | FileCheck %s --check-prefix=CHECK --check-prefix=SAFE
; RUN: llc < %s -mtriple=powerpc64-unknown-unknown -mcpu=pwr7 -mattr=-vsx \
; RUN: -enable-no-infs-fp-math -enable-no-nans-fp-math \
; RUN: | FileCheck %s --check-prefix=CHECK --check-prefix=UNSAFE
; The fcmp+select in these functions should be converted to a fsel instruction
; when both NoInfsFPMath and NoNaNsInFPMath are enabled.
; CHECK-LABEL: default0:
define double @default0(double %a, double %y, double %z) {
entry:
; SAFE-NOT: fsel
; UNSAFE: fsel
%cmp = fcmp ult double %a, 0.000000e+00
%z.y = select i1 %cmp, double %z, double %y
ret double %z.y
}
; CHECK-LABEL: unsafe_math_off:
define double @unsafe_math_off(double %a, double %y, double %z) #0 #2 {
entry:
; SAFE-NOT: fsel
; UNSAFE-NOT: fsel
%cmp = fcmp ult double %a, 0.000000e+00
%z.y = select i1 %cmp, double %z, double %y
ret double %z.y
}
; CHECK-LABEL: default1:
define double @default1(double %a, double %y, double %z) {
; SAFE-NOT: fsel
; UNSAFE: fsel
%cmp = fcmp ult double %a, 0.000000e+00
%z.y = select i1 %cmp, double %z, double %y
ret double %z.y
}
; CHECK-LABEL: unsafe_math_on:
define double @unsafe_math_on(double %a, double %y, double %z) #1 #3 {
entry:
; SAFE-NOT: fsel
; UNSAFE-NOT: fsel
%cmp = fcmp ult double %a, 0.000000e+00
%z.y = select i1 %cmp, double %z, double %y
ret double %z.y
}
; CHECK-LABEL: default2:
define double @default2(double %a, double %y, double %z) {
; SAFE-NOT: fsel
; UNSAFE: fsel
%cmp = fcmp ult double %a, 0.000000e+00
%z.y = select i1 %cmp, double %z, double %y
ret double %z.y
}
attributes #0 = { "no-infs-fp-math"="false" }
attributes #1 = { "no-nans-fp-math"="false" }
attributes #2 = { "no-infs-fp-math"="false" }
attributes #3 = { "no-infs-fp-math"="true" }