In the CBackend, use casts to force integer add, subtract, and

multiply to be done as unsigned, so that they have well defined
behavior on overflow. This fixes PR2408.

llvm-svn: 53767

2 files changed, 14 insertions, 1 deletions

diff --git a/llvm/test/CodeGen/CBackend/2007-02-23-NameConflicts.ll b/llvm/test/CodeGen/CBackend/2007-02-23-NameConflicts.ll
index 2bc4d516808..eb5cb864465 100644
--- a/llvm/test/CodeGen/CBackend/2007-02-23-NameConflicts.ll
+++ b/llvm/test/CodeGen/CBackend/2007-02-23-NameConflicts.ll
@@ -1,7 +1,8 @@
 ; PR1164
 ; RUN: llvm-as < %s | llc -march=c | grep {llvm_cbe_A = \\*llvm_cbe_G;}
 ; RUN: llvm-as < %s | llc -march=c | grep {llvm_cbe_B = \\*(&ltmp_0_1);}
-; RUN: llvm-as < %s | llc -march=c | grep {return (llvm_cbe_A + llvm_cbe_B);}
+; RUN: llvm-as < %s | llc -march=c | grep {return (((unsigned int )(((unsigned int )llvm_cbe_A) + ((unsigned int )llvm_cbe_B))));}
+
 @G = global i32 123
 @ltmp_0_1 = global i32 123
 
diff --git a/llvm/test/CodeGen/CBackend/pr2408.ll b/llvm/test/CodeGen/CBackend/pr2408.ll
new file mode 100644
index 00000000000..a16f91bfad8
--- /dev/null
+++ b/llvm/test/CodeGen/CBackend/pr2408.ll
@@ -0,0 +1,12 @@
+; RUN: llvm-as < %s | llc -march=c | grep {\\* ((unsigned int )}
+; PR2408
+
+define i32 @a(i32 %a) {
+entry:
+        %shr = ashr i32 %a, 0           ; <i32> [#uses=1]
+        %shr2 = ashr i32 2, 0           ; <i32> [#uses=1]
+        %mul = mul i32 %shr, %shr2              ; <i32> [#uses=1]
+        %shr4 = ashr i32 2, 0           ; <i32> [#uses=1]
+        %div = sdiv i32 %mul, %shr4             ; <i32> [#uses=1]
+        ret i32 %div
+}