[clang] [llvm] [ARM] Save floating point registers and status registers with save_fp function attribute (PR #89654)

[Eli Friedman via cfe-commits]

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@@ -0,0 +1,34 @@
+// REQUIRES: arm-registered-target
+// RUN: %clang -target arm-none-none-eabihf -mcpu=cortex-r5 -mfpu=vfpv3-d16 -marm -S -o - %s \
+// RUN: | FileCheck %s --check-prefix=CHECK-R
+// RUN: %clang -target arm-none-none-eabihf -mcpu=cortex-r5 -mfpu=vfpv3-d16 -mthumb -S -o - %s \
+// RUN: | FileCheck %s --check-prefix=CHECK-R
+// RUN: %clang -target arm-none-none-eabihf -mcpu=cortex-r4 -mfpu=vfpv3-d16 -marm -S -o - %s \
+// RUN: | FileCheck %s --check-prefix=CHECK-R
+// RUN: %clang -target arm-none-none-eabihf -mcpu=cortex-r4 -mfpu=vfpv3-d16 -mthumb -S -o - %s \
+// RUN: | FileCheck %s --check-prefix=CHECK-R
+// RUN: %clang -target arm-none-none-eabihf -mcpu=cortex-m4 -mfpu=fpv4-sp-d16 -S -o - %s \
+// RUN: | FileCheck %s --check-prefix=CHECK-M
+// RUN: %clang -target arm-none-none-eabihf -mcpu=cortex-m33 -mfpu=fpv5-sp-d16 -S -o - %s \
+// RUN: | FileCheck %s --check-prefix=CHECK-M
+
+void bar();
+
+__attribute__((interrupt_save_fp)) void test_generic_interrupt() {
+    // CHECK-R:      vmrs	r4, fpscr
+    // CHECK-R-NEXT: vmrs	r5, fpexc
+    // CHECK-R-NEXT: .save  {fpscr, fpexc}
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efriedma-quic wrote:

At that point, you might as well not emit the .save at all?  At best, the debugger will just see the values get overwritten, and ignore the second .save.

https://github.com/llvm/llvm-project/pull/89654