Implement support for -fwrapv, rdar://7221421

As part of this, pull together trapv handling into the same enum.

This also add support for NSW multiplies.

This also makes PCH disagreement on overflow behavior silent, since it
really doesn't matter except for warnings and codegen (no macros get 
defined etc).

llvm-svn: 106956

1 files changed, 33 insertions, 0 deletions

diff --git a/clang/test/CodeGen/integer-overflow.c b/clang/test/CodeGen/integer-overflow.c
new file mode 100644
index 00000000000..79692161042
--- /dev/null
+++ b/clang/test/CodeGen/integer-overflow.c
@@ -0,0 +1,33 @@
+// RUN: %clang_cc1 %s -emit-llvm -o - | FileCheck %s --check-prefix=DEFAULT
+// RUN: %clang_cc1 %s -emit-llvm -o - -fwrapv | FileCheck %s --check-prefix=WRAPV
+// RUN: %clang_cc1 %s -emit-llvm -o - -ftrapv | FileCheck %s --check-prefix=TRAPV
+
+
+// Tests for signed integer overflow stuff.
+// rdar://7432000 rdar://7221421
+void test1() {
+  // DEFAULT: define void @test1
+  // WRAPV: define void @test1
+  // TRAPV: define void @test1
+  extern volatile int f11G, a, b;
+  
+  // DEFAULT: add nsw i32
+  // WRAPV: add i32
+  // TRAPV: llvm.sadd.with.overflow.i32
+  f11G = a + b;
+  
+  // DEFAULT: sub nsw i32
+  // WRAPV: sub i32
+  // TRAPV: llvm.ssub.with.overflow.i32
+  f11G = a - b;
+  
+  // DEFAULT: sub nsw i32 0, 
+  // WRAPV: sub i32 0, 
+  // TRAPV: sub nsw i32 0, 
+  f11G = -a;
+  
+  // DEFAULT: mul nsw i32
+  // WRAPV: mul i32
+  // TRAPV: llvm.smul.with.overflow.i32
+  f11G = a * b;
+}