Mark setjmp as "returns twice" and turn off SimpleCoalescing when called.

tests_lit/llvm2ice_tests/returns_twice_no_coalesce.ll

Index: tests_lit/llvm2ice_tests/returns_twice_no_coalesce.ll
diff --git a/tests_lit/llvm2ice_tests/returns_twice_no_coalesce.ll b/tests_lit/llvm2ice_tests/returns_twice_no_coalesce.ll
new file mode 100644
index 0000000000000000000000000000000000000000..754a105b01591191e3a267314e3f31a5bacf1722
--- /dev/null
+++ b/tests_lit/llvm2ice_tests/returns_twice_no_coalesce.ll
@@ -0,0 +1,60 @@
+; This file checks that SimpleCoalescing of local stack slots is not done
+; when calling a function with the "returns twice" attribute.
+
+; RUN: %llvm2ice -Om1 --verbose none %s \
+; RUN:   | llvm-mc -triple=i686-none-nacl -x86-asm-syntax=intel -filetype=obj \
+; RUN:   | llvm-objdump -d --symbolize -x86-asm-syntax=intel - | FileCheck %s
+; RUN: %llvm2ice --verbose none %s | FileCheck --check-prefix=ERRORS %s
+
+; Setjmp is a function with the "returns twice" attribute.
+declare i32 @llvm.nacl.setjmp(i8*)
+
+declare i32 @other(i32)
+declare void @user(i32)
+
+define i32 @call_returns_twice(i32 %iptr_jmpbuf, i32 %x) {
+entry:
+  %local = add i32 %x, 12345
+  %jmpbuf = inttoptr i32 %iptr_jmpbuf to i8*
+  %y = call i32 @llvm.nacl.setjmp(i8* %jmpbuf)
+  call void @user(i32 %local)
+  %cmp = icmp eq i32 %y, 0
+  br i1 %cmp, label %Zero, label %NonZero
+Zero:
+  %other_local = add i32 %x, 54321
+  call void @user(i32 %other_local)
+  ret i32 %other_local
+NonZero:
+  ret i32 1
+}
+
+; CHECK-LABEL: call_returns_twice
+; CHECK: add [[REG1:.*]], 12345
+; CHECK: mov dword ptr [esp + [[OFF:.*]]], [[REG1]]
+; CHECK: add [[REG2:.*]], 54321
+; There should not be sharing of the stack slot.
+; CHECK-NOT: mov dword ptr [esp + [[OFF]]], [[REG2]]
+
+define i32 @no_call_returns_twice(i32 %iptr_jmpbuf, i32 %x) {
+entry:
+  %local = add i32 %x, 12345
+  %y = call i32 @other(i32 %x)
+  call void @user(i32 %local)
+  %cmp = icmp eq i32 %y, 0
+  br i1 %cmp, label %Zero, label %NonZero
+Zero:
+  %other_local = add i32 %x, 54321
+  call void @user(i32 %other_local)
+  ret i32 %other_local
+NonZero:
+  ret i32 1
+}
+
+; CHECK-LABEL: no_call_returns_twice
+; CHECK: add [[REG1:.*]], 12345
+; CHECK: mov dword ptr [esp + [[OFF:.*]]], [[REG1]]
+; CHECK: add [[REG2:.*]], 54321
+; Now there should be sharing of the stack slot (OFF is the same).
+; CHECK: mov dword ptr [esp + [[OFF]]], [[REG2]]
+
+; ERRORS-NOT: ICE translation error