[ARM] Reapply r296865 "[ARM] fpscr read/write intrinsics not aware of each other""

The original patch r296865 was reverted as it broke the chromium builds for
Android https://bugs.llvm.org/show_bug.cgi?id=32134, this patch reapplies
r296865 with a fix to make sure it doesn't cause the build regression.

The problem was that intrinsic selection on int_arm_get_fpscr was failing in
ISel this was because the code to manually select this intrinsic still thought
it was the version with no side-effects (INTRINSIC_WO_CHAIN) which is wrong as
it doesn't semantically match the definition in the tablegen code which says it
does have side-effects, I've fixed this by updating the intrinsic type to
INTRINSIC_W_CHAIN (has side-effects). I've also added a test for this based on
Hans original reproducer.

Differential Revision: https://reviews.llvm.org/D30645

llvm-svn: 297137

1 files changed, 44 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/ARM/fpscr-intrinsics.ll b/llvm/test/CodeGen/ARM/fpscr-intrinsics.ll
new file mode 100644
index 00000000000..64b97525feb
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/fpscr-intrinsics.ll
@@ -0,0 +1,44 @@
+; RUN: llc < %s -O0 -mtriple=armv7-eabi -mcpu=cortex-a8 -mattr=+neon,+fp-armv8 | FileCheck %s
+; RUN: llc < %s -O3 -mtriple=armv7-eabi -mcpu=cortex-a8 -mattr=+neon,+fp-armv8 | FileCheck %s
+
+@a = common global double 0.000000e+00, align 8
+
+; Function Attrs: noinline nounwind uwtable
+define void @strtod() {
+entry:
+  ; CHECK: vmrs r{{[0-9]+}}, fpscr
+  %0 = call i32 @llvm.flt.rounds()
+  %tobool = icmp ne i32 %0, 0
+  br i1 %tobool, label %if.then, label %if.end
+
+if.then:                                          ; preds = %entry
+  store double 5.000000e-01, double* @a, align 8
+  br label %if.end
+
+if.end:                                           ; preds = %if.then, %entry
+  ret void
+}
+
+; Function Attrs: nounwind
+define void @fn1(i32* nocapture %p) local_unnamed_addr {
+entry:
+  ; CHECK: vmrs r{{[0-9]+}}, fpscr
+  %0 = tail call i32 @llvm.arm.get.fpscr()
+  store i32 %0, i32* %p, align 4
+  ; CHECK: vmsr fpscr, r{{[0-9]+}}
+  tail call void @llvm.arm.set.fpscr(i32 1)
+  ; CHECK: vmrs r{{[0-9]+}}, fpscr
+  %1 = tail call i32 @llvm.arm.get.fpscr()
+  %arrayidx1 = getelementptr inbounds i32, i32* %p, i32 1
+  store i32 %1, i32* %arrayidx1, align 4
+  ret void
+}
+
+; Function Attrs: nounwind readonly
+declare i32 @llvm.arm.get.fpscr()
+
+; Function Attrs: nounwind writeonly
+declare void @llvm.arm.set.fpscr(i32)
+
+; Function Attrs: nounwind
+declare i32 @llvm.flt.rounds()