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

3 files changed, 132 insertions, 2 deletions

diff --git a/llvm/test/CodeGen/ARM/sub.ll b/llvm/test/CodeGen/ARM/sub.ll
new file mode 100644
index 00000000000..81513e23e80
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/sub.ll
@@ -0,0 +1,29 @@
+; RUN: llc -march=arm < %s | FileCheck %s
+
+; 171 = 0x000000ab
+define i64 @f1(i64 %a) {
+; CHECK: f1
+; CHECK: subs r0, r0, #171
+; CHECK: sbc r1, r1, #0
+    %tmp = sub i64 %a, 171
+    ret i64 %tmp
+}
+
+; 66846720 = 0x03fc0000
+define i64 @f2(i64 %a) {
+; CHECK: f2
+; CHECK: subs r0, r0, #255, 14
+; CHECK: sbc r1, r1, #0
+    %tmp = sub i64 %a, 66846720
+    ret i64 %tmp
+}
+
+; 734439407618 = 0x000000ab00000002
+define i64 @f3(i64 %a) {
+; CHECK: f3
+; CHECK: subs r0, r0, #2
+; CHECK: sbc r1, r1, #171
+   %tmp = sub i64 %a, 734439407618
+   ret i64 %tmp
+}
+
diff --git a/llvm/test/CodeGen/Thumb2/thumb2-sbc.ll b/llvm/test/CodeGen/Thumb2/thumb2-sbc.ll
index ad962919edc..de6502d2e63 100644
--- a/llvm/test/CodeGen/Thumb2/thumb2-sbc.ll
+++ b/llvm/test/CodeGen/Thumb2/thumb2-sbc.ll
@@ -1,8 +1,54 @@
-; RUN: llc < %s -march=thumb -mattr=+thumb2 | FileCheck %s
+; RUN: llc -march=thumb -mattr=+thumb2 < %s | FileCheck %s
 
 define i64 @f1(i64 %a, i64 %b) {
-; CHECK: f1:
+; CHECK: f1
 ; CHECK: subs r0, r0, r2
     %tmp = sub i64 %a, %b
     ret i64 %tmp
 }
+
+; 734439407618 = 0x000000ab00000002
+define i64 @f2(i64 %a) {
+; CHECK: f2
+; CHECK: subs r0, #2
+; CHECK: sbc r1, r1, #171
+    %tmp = sub i64 %a, 734439407618
+    ret i64 %tmp
+}
+
+; 5066626890203138 = 0x0012001200000002
+define i64 @f3(i64 %a) {
+; CHECK: f3
+; CHECK: subs  r0, #2
+; CHECK: sbc r1, r1, #1179666
+    %tmp = sub i64 %a, 5066626890203138
+    ret i64 %tmp
+}
+
+; 3747052064576897026 = 0x3400340000000002
+define i64 @f4(i64 %a) {
+; CHECK: f4
+; CHECK: subs  r0, #2
+; CHECK: sbc r1, r1, #872428544
+    %tmp = sub i64 %a, 3747052064576897026
+    ret i64 %tmp
+}
+
+; 6221254862626095106 = 0x5656565600000002
+define i64 @f5(i64 %a) {
+; CHECK: f5
+; CHECK: subs  r0, #2
+; CHECK: adc r1, r1, #-1448498775
+    %tmp = sub i64 %a, 6221254862626095106 
+    ret i64 %tmp
+}
+
+; 287104476244869122 = 0x03fc000000000002
+define i64 @f6(i64 %a) {
+; CHECK: f6
+; CHECK: subs  r0, #2
+; CHECK: sbc r1, r1, #66846720
+    %tmp = sub i64 %a, 287104476244869122 
+    ret i64 %tmp
+}
+
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
+}