AMDGPU: mark ldexp LibCalls as unavailable

Summary:
The LibCallSimplifier will turn llvm.exp2.* intrinsics into ldexp* libcalls
which do not make sense with the AMDGPU backend.

In the long run, we'll want an llvm.ldexp.* intrinsic to properly make use of
this optimization, but this works around the problem for now.

See also: http://reviews.llvm.org/D14327 (suggested llvm.ldexp.* implementation)
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92709

Reviewers: arsenm, tstellarAMD

Differential Revision: http://reviews.llvm.org/D14990

llvm-svn: 255658
This commit is contained in:
Nicolai Hahnle 2015-12-15 17:24:15 +00:00
parent 8f307217c3
commit 78fd4f087b
2 changed files with 16 additions and 10 deletions
llvm
lib/Analysis
test/Transforms/InstCombine

View File

@ -61,6 +61,13 @@ static void initialize(TargetLibraryInfoImpl &TLI, const Triple &T,
}
#endif // !NDEBUG
if (T.getArch() == Triple::r600 ||
T.getArch() == Triple::amdgcn) {
TLI.setUnavailable(LibFunc::ldexp);
TLI.setUnavailable(LibFunc::ldexpf);
TLI.setUnavailable(LibFunc::ldexpl);
}
// There are no library implementations of mempcy and memset for AMD gpus and
// these can be difficult to lower in the backend.
if (T.getArch() == Triple::r600 ||

View File

@ -1,7 +1,8 @@
; Test that the exp2 library call simplifier works correctly.
;
; RUN: opt < %s -instcombine -S | FileCheck %s
; RUN: opt < %s -instcombine -S -mtriple=i386-pc-win32 | FileCheck %s -check-prefix=CHECK-WIN
; RUN: opt < %s -instcombine -S | FileCheck %s -check-prefix=CHECK -check-prefix=INTRINSIC -check-prefix=LDEXP -check-prefix=LDEXPF
; RUN: opt < %s -instcombine -S -mtriple=i386-pc-win32 | FileCheck %s -check-prefix=INTRINSIC -check-prefix=LDEXP -check-prefix=NOLDEXPF
; RUN: opt < %s -instcombine -S -mtriple=amdgcn-unknown-unknown | FileCheck %s -check-prefix=INTRINSIC -check-prefix=NOLDEXP -check-prefix=NOLDEXPF
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
@ -80,21 +81,19 @@ declare double @llvm.exp2.f64(double)
declare float @llvm.exp2.f32(float)
define double @test_simplify9(i8 zeroext %x) {
; CHECK-LABEL: @test_simplify9(
; CHECK-WIN-LABEL: @test_simplify9(
; INTRINSIC-LABEL: @test_simplify9(
%conv = uitofp i8 %x to double
%ret = call double @llvm.exp2.f64(double %conv)
; CHECK: call double @ldexp
; CHECK-WIN: call double @ldexp
; LDEXP: call double @ldexp
; NOLDEXP-NOT: call double @ldexp
ret double %ret
}
define float @test_simplify10(i8 zeroext %x) {
; CHECK-LABEL: @test_simplify10(
; CHECK-WIN-LABEL: @test_simplify10(
; INTRINSIC-LABEL: @test_simplify10(
%conv = uitofp i8 %x to float
%ret = call float @llvm.exp2.f32(float %conv)
; CHECK: call float @ldexpf
; CHECK-WIN-NOT: call float @ldexpf
; LDEXPF: call float @ldexpf
; NOLDEXPF-NOT: call float @ldexpf
ret float %ret
}