[Analysis] Disable exp/exp2/pow finite lib calls on Android with -ffast-math.

Summary:
Since r322087, glibc's finite lib calls are generated when possible.
However, glibc is not supported on Android. Therefore this change
enables llvm to finely distinguish between linux and Android for
unsupported library calls. The change also include some regression
tests.

Reviewers: srhines, pirama

Reviewed By: srhines

Subscribers: kongyi, chh, javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D42288

llvm-svn: 323187

2 files changed, 38 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/TargetLibraryInfo.cpp b/llvm/lib/Analysis/TargetLibraryInfo.cpp
index f655eaeca52..2dbcc9fa6f2 100644
--- a/llvm/lib/Analysis/TargetLibraryInfo.cpp
+++ b/llvm/lib/Analysis/TargetLibraryInfo.cpp
@@ -397,6 +397,15 @@ static void initialize(TargetLibraryInfoImpl &TLI, const Triple &T,
     TLI.setUnavailable(LibFunc_flsll);
   }
 
+  // Android uses bionic instead of glibc. So disable some finite
+  // lib calls in glibc for Android. The list of unsupported lib
+  // calls for Android may expand as the need arises.
+  if (T.isAndroid()) {
+    TLI.setUnavailable(LibFunc_exp_finite);
+    TLI.setUnavailable(LibFunc_exp2_finite);
+    TLI.setUnavailable(LibFunc_pow_finite);
+  }
+
   // The following functions are available on at least Linux:
   if (!T.isOSLinux()) {
     TLI.setUnavailable(LibFunc_dunder_strdup);
diff --git a/llvm/test/CodeGen/AArch64/illegal-float-ops.ll b/llvm/test/CodeGen/AArch64/illegal-float-ops.ll
index 9f7dd998bc2..81a3abd2bd9 100644
--- a/llvm/test/CodeGen/AArch64/illegal-float-ops.ll
+++ b/llvm/test/CodeGen/AArch64/illegal-float-ops.ll
@@ -1,4 +1,5 @@
 ; RUN: llc -mtriple=aarch64-none-linux-gnu -verify-machineinstrs -o - %s | FileCheck %s
+; RUN: llc -mtriple=aarch64-linux-android -verify-machineinstrs -o - %s | FileCheck --check-prefix=ANDROID-AARCH64 %s
 
 @varfloat = global float 0.0
 @vardouble = global double 0.0
@@ -245,3 +246,31 @@ define void @test_fmuladd(fp128 %fp128) {
 
   ret void
 }
+
+define void @test_exp_finite(double %double) #0 {
+  %expdouble = call double @llvm.exp.f64(double %double)
+  store double %expdouble, double* @vardouble
+  ; ANDROID-AARCH64-NOT: bl __exp_finite
+  ; CHECK: bl __exp_finite
+
+  ret void
+}
+
+define void @test_exp2_finite(double %double) #0 {
+  %expdouble = call double @llvm.exp2.f64(double %double)
+  store double %expdouble, double* @vardouble
+  ; ANDROID-AARCH64-NOT: bl __exp2_finite
+  ; CHECK: bl __exp2_finite
+
+  ret void
+}
+
+define void @test_pow_finite(double %double) #0 {
+  %powdouble = call double @llvm.pow.f64(double %double, double %double)
+  store double %powdouble, double* @vardouble
+  ; ANDROID-AARCH64-NOT: bl __pow_finite
+  ; CHECK: bl __pow_finite
+  ret void
+}
+
+attributes #0 = { "no-infs-fp-math"="true" "no-nans-fp-math"="true" }