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[Thumb1] Fix the bug when adding/subtracting -2147483648 

Differential Revision: https://reviews.llvm.org/D30829

llvm-svn: 297820
This commit is contained in:
Artyom Skrobov 2017-03-15 10:19:16 +00:00
parent c179662807
commit 3fa5fd1dd2
2 changed files with 16 additions and 4 deletions
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8
llvm/lib/Target/ARM/ARMISelLowering.cpp
View File

@ -9788,8 +9788,8 @@ static SDValue PerformAddcSubcCombine(SDNode *N, SelectionDAG &DAG,
if (Subtarget->isThumb1Only()) {
SDValue RHS = N->getOperand(1);
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(RHS)) {
int64_t imm = C->getSExtValue();
if (imm < 0) {
int32_t imm = C->getSExtValue();
if (-imm > 0) {
SDLoc DL(N);
RHS = DAG.getConstant(-imm, DL, MVT::i32);
unsigned Opcode = (N->getOpcode() == ARMISD::ADDC) ? ARMISD::SUBC
@ -9806,8 +9806,8 @@ static SDValue PerformAddeSubeCombine(SDNode *N, SelectionDAG &DAG,
if (Subtarget->isThumb1Only()) {
SDValue RHS = N->getOperand(1);
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(RHS)) {
int64_t imm = C->getSExtValue();
if (imm < 0) {
int32_t imm = C->getSExtValue();
if (-imm > 0) {
SDLoc DL(N);
// The with-carry-in form matches bitwise not instead of the negation.

12
llvm/test/CodeGen/Thumb/long.ll
View File

@ -194,3 +194,15 @@ entry:
; CHECK: movs r1, r3
}
; "sub 2147483648" has to be lowered into "add -2147483648"
define i64 @f12(i64 %x, i64 %y) {
entry:
%tmp1 = sub i64 %x, 2147483648
ret i64 %tmp1
; CHECK-LABEL: f12:
; CHECK: movs r2, #1
; CHECK: lsls r2, r2, #31
; CHECK: movs r3, #0
; CHECK: adds r0, r0, r2
; CHECK: sbcs r1, r3
}