[clang] Don't do casting of atomic FP loads/stores in FE. (PR #83446)

[Matt Arsenault via cfe-commits]

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@@ -0,0 +1,84 @@
+// RUN: %clang_cc1 -triple s390x-linux-gnu -O1 -emit-llvm %s -o - | FileCheck %s
+//
+// Test that floating point atomic stores and loads do not get casted to/from
+// integer.
+
+#include <stdatomic.h>
+
+_Atomic float Af;
+_Atomic double Ad;
+_Atomic long double Ald;
+
+//// Atomic stores of floating point values.
+void fun0(float Arg) {
+// CHECK-LABEL: @fun0
+// CHECK:       store atomic float %Arg, ptr @Af seq_cst, align 4
+  Af = Arg;
+}
+
+void fun1(double Arg) {
+// CHECK-LABEL: @fun1
+// CHECK:       store atomic double %Arg, ptr @Ad seq_cst, align 8
+  Ad = Arg;
+}
+
+void fun2(long double Arg) {
+// CHECK-LABEL: @fun2
+// CHECK:       store atomic fp128 %Arg, ptr @Ald seq_cst, align 16
+  Ald = Arg;
+}
+
+void fun3(_Atomic float *Dst, float Arg) {
+// CHECK-LABEL: @fun
+// CHECK:       store atomic float %Arg, ptr %Dst seq_cst, align 4
+  *Dst = Arg;
+}
+
+void fun4(_Atomic double *Dst, double Arg) {
+// CHECK-LABEL: @fun4
+// CHECK:       store atomic double %Arg, ptr %Dst seq_cst, align 8
+  *Dst = Arg;
+}
+
+void fun5(_Atomic long double *Dst, long double Arg) {
+// CHECK-LABEL: @fun5
+// CHECK:       store atomic fp128 %Arg, ptr %Dst seq_cst, align 16
+  *Dst = Arg;
+}
+
+//// Atomic loads of floating point values.
+float fun6() {
+// CHECK-LABEL: @fun6
+// CHECK:       %atomic-load = load atomic float, ptr @Af seq_cst, align 4
+  return Af;
+}
+
+float fun7() {
+// CHECK-LABEL: @fun7
+// CHECK:       %atomic-load = load atomic double, ptr @Ad seq_cst, align 8
+  return Ad;
+}
+
+float fun8() {
+// CHECK-LABEL: @fun8
+// CHECK:       %atomic-load = load atomic fp128, ptr @Ald seq_cst, align 16
+  return Ald;
+}
+
+float fun9(_Atomic float *Src) {
+// CHECK-LABEL: @fun9
+// CHECK:       %atomic-load = load atomic float, ptr %Src seq_cst, align 4
+  return *Src;
+}
+
+double fun10(_Atomic double *Src) {
+// CHECK-LABEL: @fun10
+// CHECK:       %atomic-load = load atomic double, ptr %Src seq_cst, align 8
+  return *Src;
+}
+
+long double fun11(_Atomic long double *Src) {
+// CHECK-LABEL: @fun11
+// CHECK:       %atomic-load = load atomic fp128, ptr %Src seq_cst, align 16
+  return *Src;
+}
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arsenm wrote:

test the volatile is preserved too? 

https://github.com/llvm/llvm-project/pull/83446