[clang] [clang] fix half && bfloat16 convert node expr codegen (PR #89051)

[Matt Arsenault via cfe-commits]

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@@ -0,0 +1,25 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -disable-O0-optnone -emit-llvm \
+// RUN:   %s -o - | opt -S -passes=mem2reg | FileCheck %s
+
+// CHECK-LABEL: define dso_local half @test_convert_from_bf16_to_fp16(
+// CHECK-SAME: bfloat noundef [[A:%.*]]) #[[ATTR0:[0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[FPEXT:%.*]] = fpext bfloat [[A]] to float
+// CHECK-NEXT:    [[FPTRUNC:%.*]] = fptrunc float [[FPEXT]] to half
+// CHECK-NEXT:    ret half [[FPTRUNC]]
+//
+_Float16 test_convert_from_bf16_to_fp16(__bf16 a) {
+    return (_Float16)a;
+}
+
+// CHECK-LABEL: define dso_local bfloat @test_convert_from_fp16_to_bf16(
+// CHECK-SAME: half noundef [[A:%.*]]) #[[ATTR0]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[FPEXT:%.*]] = fpext half [[A]] to float
+// CHECK-NEXT:    [[FPTRUNC:%.*]] = fptrunc float [[FPEXT]] to bfloat
+// CHECK-NEXT:    ret bfloat [[FPTRUNC]]
+//
+__bf16 test_convert_from_fp16_to_bf16(_Float16 a) {
+    return (__bf16)a;
+}
+
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arsenm wrote:

The regular C case should still test the vector conversions. Also the rebase is confusing me 

https://github.com/llvm/llvm-project/pull/89051