1 files changed, 57 insertions, 12 deletions
diff --git a/test/CodeGen/Thumb/large-stack.ll b/test/CodeGen/Thumb/large-stack.ll
index fb6daa4..269bdd9 100644
--- a/test/CodeGen/Thumb/large-stack.ll
+++ b/test/CodeGen/Thumb/large-stack.ll
@@ -1,31 +1,57 @@
-; RUN: llc < %s -mtriple=thumb-apple-ios | FileCheck %s
+; RUN: llc < %s -mtriple=thumb-apple-ios | FileCheck %s --check-prefix=CHECK --check-prefix=IOS
+; RUN: llc < %s -mtriple=thumb-none-eabi | FileCheck %s --check-prefix=CHECK --check-prefix=EABI
+; RUN: llc < %s -o %t -filetype=obj -mtriple=thumbv6-apple-ios
+; RUN: llvm-objdump -triple=thumbv6-apple-ios -d %t | FileCheck %s --check-prefix=CHECK --check-prefix=IOS
+; RUN: llc < %s -o %t -filetype=obj -mtriple=thumbv6-none-eabi
+; RUN: llvm-objdump -triple=thumbv6-none-eabi -d %t | FileCheck %s --check-prefix=CHECK --check-prefix=EABI
 
+; Largest stack for which a single tADDspi/tSUBspi is enough
 define void @test1() {
 ; CHECK-LABEL: test1:
-; CHECK: sub sp, #256
-; CHECK: add sp, #256
-    %tmp = alloca [ 64 x i32 ] , align 4
+; CHECK: sub sp, #508
+; CHECK: add sp, #508
+    %tmp = alloca [ 508 x i8 ] , align 4
     ret void
 }
 
+; Largest stack for which three tADDspi/tSUBspis are enough
+define void @test100() {
+; CHECK-LABEL: test100:
+; CHECK: sub sp, #508
+; CHECK: sub sp, #508
+; CHECK: sub sp, #508
+; EABI: add sp, #508
+; EABI: add sp, #508
+; EABI: add sp, #508
+; IOS: subs r4, r7, #4
+; IOS: mov sp, r4
+    %tmp = alloca [ 1524 x i8 ] , align 4
+    ret void
+}
+
+; Smallest stack for which we use a constant pool
 define void @test2() {
 ; CHECK-LABEL: test2:
-; CHECK: ldr r0, LCPI
+; CHECK: ldr r0,
 ; CHECK: add sp, r0
-; CHECK: subs r4, r7, #4
-; CHECK: mov sp, r4
-    %tmp = alloca [ 4168 x i8 ] , align 4
+; EABI: ldr r0,
+; EABI: add sp, r0
+; IOS: subs r4, r7, #4
+; IOS: mov sp, r4
+    %tmp = alloca [ 1528 x i8 ] , align 4
     ret void
 }
 
 define i32 @test3() {
 ; CHECK-LABEL: test3:
-; CHECK: ldr r1, LCPI
+; CHECK: ldr r1,
 ; CHECK: add sp, r1
-; CHECK: ldr r1, LCPI
+; CHECK: ldr r1,
 ; CHECK: add r1, sp
-; CHECK: subs r4, r7, #4
-; CHECK: mov sp, r4
+; EABI: ldr r1,
+; EABI: add sp, r1
+; IOS: subs r4, r7, #4
+; IOS: mov sp, r4
     %retval = alloca i32, align 4
     %tmp = alloca i32, align 4
     %a = alloca [805306369 x i8], align 16
@@ -33,3 +59,22 @@ define i32 @test3() {
     %tmp1 = load i32* %tmp
     ret i32 %tmp1
 }
+
+; Here, the adds get optimized out because they are dead, but the calculation
+; of the address of stack_a is dead but not optimized out. When the address
+; calculation gets expanded to two instructions, we need to avoid reading a
+; dead register.
+; No CHECK lines (just test for crashes), as we hope this will be optimised
+; better in future.
+define i32 @test4() {
+entry:
+  %stack_a = alloca i8, align 1
+  %stack_b = alloca [256 x i32*], align 4
+  %int = ptrtoint i8* %stack_a to i32
+  %add = add i32 %int, 1
+  br label %block2
+
+block2:
+  %add2 = add i32 %add, 1
+  ret i32 0
+}