Improve 64-subtraction of immediates when parts of the immediate can fit

in the literal field of an instruction. E.g.,
long long foo(long long a) {
  return a - 734439407618LL;
}

rdar://7038284

llvm-svn: 108339

1 files changed, 55 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/Thumb2/thumb2-sub3.ll b/llvm/test/CodeGen/Thumb2/thumb2-sub3.ll
new file mode 100644
index 00000000000..855ad06a63f
--- /dev/null
+++ b/llvm/test/CodeGen/Thumb2/thumb2-sub3.ll
@@ -0,0 +1,55 @@
+; RUN: llc -march=thumb -mattr=+thumb2 < %s | FileCheck %s
+
+; 171 = 0x000000ab
+define i64 @f1(i64 %a) {
+; CHECK: f1
+; CHECK: subs  r0, #171
+; CHECK: adc r1, r1, #-1
+    %tmp = sub i64 %a, 171
+    ret i64 %tmp
+}
+
+; 1179666 = 0x00120012
+define i64 @f2(i64 %a) {
+; CHECK: f2
+; CHECK: subs.w  r0, r0, #1179666
+; CHECK: adc r1, r1, #-1
+    %tmp = sub i64 %a, 1179666
+    ret i64 %tmp
+}
+
+; 872428544 = 0x34003400
+define i64 @f3(i64 %a) {
+; CHECK: f3
+; CHECK: subs.w  r0, r0, #872428544
+; CHECK: adc r1, r1, #-1
+    %tmp = sub i64 %a, 872428544
+    ret i64 %tmp
+}
+
+; 1448498774 = 0x56565656
+define i64 @f4(i64 %a) {
+; CHECK: f4
+; CHECK: subs.w  r0, r0, #1448498774
+; CHECK: adc r1, r1, #-1
+    %tmp = sub i64 %a, 1448498774
+    ret i64 %tmp
+}
+
+; 66846720 = 0x03fc0000
+define i64 @f5(i64 %a) {
+; CHECK: f5
+; CHECK: subs.w  r0, r0, #66846720
+; CHECK: adc r1, r1, #-1
+    %tmp = sub i64 %a, 66846720
+    ret i64 %tmp
+}
+
+; 734439407618 = 0x000000ab00000002
+define i64 @f6(i64 %a) {
+; CHECK: f6
+; CHECK: subs r0, #2
+; CHECK: sbc r1, r1, #171
+   %tmp = sub i64 %a, 734439407618
+   ret i64 %tmp
+}