[Thumb] Fix off-by-one error in r272007
We can only generate immediates up to #510 with a MOV+ADD, not #511, because there's no such instruction as add #256.
Found by Oliver Stannard and csmith!
llvm-svn: 272665
diff --git a/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp b/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
index 061c4b7..4af2174 100644
--- a/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -485,7 +485,7 @@
if (Subtarget->isThumb()) {
if (Val <= 255) return 1; // MOV
if (Subtarget->hasV6T2Ops() && Val <= 0xffff) return 1; // MOVW
- if (Val <= 511) return 2; // MOV + ADDi8
+ if (Val <= 510) return 2; // MOV + ADDi8
if (~Val <= 255) return 2; // MOV + MVN
if (ARM_AM::isThumbImmShiftedVal(Val)) return 2; // MOV + LSL
} else {
diff --git a/llvm/lib/Target/ARM/ARMInstrThumb.td b/llvm/lib/Target/ARM/ARMInstrThumb.td
index e9b49f9..5d4698f 100644
--- a/llvm/lib/Target/ARM/ARMInstrThumb.td
+++ b/llvm/lib/Target/ARM/ARMInstrThumb.td
@@ -66,11 +66,11 @@
return CurDAG->getTargetConstant(V, SDLoc(N), MVT::i32);
}]>;
-def imm256_511 : ImmLeaf<i32, [{
- return Imm >= 256 && Imm < 512;
+def imm256_510 : ImmLeaf<i32, [{
+ return Imm >= 256 && Imm < 511;
}]>;
-def thumb_imm256_511_addend : SDNodeXForm<imm, [{
+def thumb_imm256_510_addend : SDNodeXForm<imm, [{
return CurDAG->getTargetConstant(N->getZExtValue() - 255, SDLoc(N), MVT::i32);
}]>;
@@ -1497,9 +1497,9 @@
def : T1Pat<(i32 imm0_255_comp:$src),
(tMVN (tMOVi8 (imm_comp_XFORM imm:$src)))>;
-def : T1Pat<(i32 imm256_511:$src),
+def : T1Pat<(i32 imm256_510:$src),
(tADDi8 (tMOVi8 255),
- (thumb_imm256_511_addend imm:$src))>;
+ (thumb_imm256_510_addend imm:$src))>;
// Pseudo instruction that combines ldr from constpool and add pc. This should
// be expanded into two instructions late to allow if-conversion and
diff --git a/llvm/test/CodeGen/Thumb/constants.ll b/llvm/test/CodeGen/Thumb/constants.ll
index 34c0813..b1145d7 100644
--- a/llvm/test/CodeGen/Thumb/constants.ll
+++ b/llvm/test/CodeGen/Thumb/constants.ll
@@ -9,3 +9,11 @@
define i32 @mov_and_add() {
ret i32 267
}
+
+; CHECK-T1-LABEL: @mov_and_add2
+; CHECK-T2-LABEL: @mov_and_add2
+; CHECK-T1: ldr r0,
+; CHECK-T2: movw r0, #511
+define i32 @mov_and_add2() {
+ ret i32 511
+}