[llvm-dev] defaults for FP contraction [e.g. fused multiply-add]: suggestion and patch to be slightly more aggressive

[Abe Skolnik via llvm-dev]

Dear all,

I have added 4 test cases that all fail on the "vanilla" [i.e. unmodified] compiler and succeed 
with my patch applied.  Please see below, presented for comments/feedback.

The only difference across the non-O0 files is the -O<something> flag; would other people 
prefer that I factor this out into one include file and 3 short stubs, if I can?

The only difference other than -O<something> between the O0 test and all the rest is that in 
the -O0 case I have removed the "CHECK-NEXT" for "ret" immediately following the "fmadd" b/c at 
-O0 the optimizer is not eliminating the boilerplate stack-related code that in this case is 
not truly needed.

Regards,

Abe






diff --git a/clang/test/CodeGen/fp-contract-pragma___on-by-default___-O0___aarch64-backend.c 
b/clang/test/CodeGen/fp-contract-pragma___on-by-default___-O0___aarch64-backend.c
new file mode 100644
index 0000000..fd4a979
--- /dev/null
+++ b/clang/test/CodeGen/fp-contract-pragma___on-by-default___-O0___aarch64-backend.c
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -triple aarch64 -O0 -S -o - %s | FileCheck %s
+// REQUIRES: aarch64-registered-target
+
+// CHECK-LABEL: fmadd_double:
+// CHECK: fmadd d0, d{{[0-7]}}, d{{[0-7]}}, d{{[0-7]}}
+double fmadd_double(double a, double b, double c) {
+  return a*b+c;
+}
+
+// CHECK-LABEL: fmadd_single:
+// CHECK: fmadd s0, s{{[0-7]}}, s{{[0-7]}}, s{{[0-7]}}
+float  fmadd_single(float  a, float  b, float  c) {
+  return a*b+c;
+}
+
diff --git a/clang/test/CodeGen/fp-contract-pragma___on-by-default___-O1___aarch64-backend.c 
b/clang/test/CodeGen/fp-contract-pragma___on-by-default___-O1___aarch64-backend.c
new file mode 100644
index 0000000..f5c55a9
--- /dev/null
+++ b/clang/test/CodeGen/fp-contract-pragma___on-by-default___-O1___aarch64-backend.c
@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 -triple aarch64 -O1 -S -o - %s | FileCheck %s
+// REQUIRES: aarch64-registered-target
+
+// CHECK-LABEL: fmadd_double:
+// CHECK: fmadd d0, d{{[0-7]}}, d{{[0-7]}}, d{{[0-7]}}
+// CHECK-NEXT: ret
+double fmadd_double(double a, double b, double c) {
+  return a*b+c;
+}
+
+// CHECK-LABEL: fmadd_single:
+// CHECK: fmadd s0, s{{[0-7]}}, s{{[0-7]}}, s{{[0-7]}}
+// CHECK-NEXT: ret
+float  fmadd_single(float  a, float  b, float  c) {
+  return a*b+c;
+}
+
diff --git a/clang/test/CodeGen/fp-contract-pragma___on-by-default___-O2___aarch64-backend.c 
b/clang/test/CodeGen/fp-contract-pragma___on-by-default___-O2___aarch64-backend.c
new file mode 100644
index 0000000..98b82a6
--- /dev/null
+++ b/clang/test/CodeGen/fp-contract-pragma___on-by-default___-O2___aarch64-backend.c
@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 -triple aarch64 -O2 -S -o - %s | FileCheck %s
+// REQUIRES: aarch64-registered-target
+
+// CHECK-LABEL: fmadd_double:
+// CHECK: fmadd d0, d{{[0-7]}}, d{{[0-7]}}, d{{[0-7]}}
+// CHECK-NEXT: ret
+double fmadd_double(double a, double b, double c) {
+  return a*b+c;
+}
+
+// CHECK-LABEL: fmadd_single:
+// CHECK: fmadd s0, s{{[0-7]}}, s{{[0-7]}}, s{{[0-7]}}
+// CHECK-NEXT: ret
+float  fmadd_single(float  a, float  b, float  c) {
+  return a*b+c;
+}
+
diff --git a/clang/test/CodeGen/fp-contract-pragma___on-by-default___-O3___aarch64-backend.c 
b/clang/test/CodeGen/fp-contract-pragma___on-by-default___-O3___aarch64-backend.c
new file mode 100644
index 0000000..4d64738
--- /dev/null
+++ b/clang/test/CodeGen/fp-contract-pragma___on-by-default___-O3___aarch64-backend.c
@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 -triple aarch64 -O3 -S -o - %s | FileCheck %s
+// REQUIRES: aarch64-registered-target
+
+// CHECK-LABEL: fmadd_double:
+// CHECK: fmadd d0, d{{[0-7]}}, d{{[0-7]}}, d{{[0-7]}}
+// CHECK-NEXT: ret
+double fmadd_double(double a, double b, double c) {
+  return a*b+c;
+}
+
+// CHECK-LABEL: fmadd_single:
+// CHECK: fmadd s0, s{{[0-7]}}, s{{[0-7]}}, s{{[0-7]}}
+// CHECK-NEXT: ret
+float  fmadd_single(float  a, float  b, float  c) {
+  return a*b+c;
+}
+