Nigel
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

ARM/Thumb2: Fix a misselect in getARMCmp, when attempting to adjust a signed 

comparison that would overflow.
 - The other under/overflow cases can't actually happen because the immediates
   which would trigger them are legal (so we don't enter this code), but
   adjusted the style to make it clear the transform is always valid.

llvm-svn: 112053
This commit is contained in:
Daniel Dunbar 2010-08-25 16:58:05 +00:00
parent 334a10a343
commit a54a1b0edf
2 changed files with 18 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
llvm/lib/Target/ARM/ARMISelLowering.cpp
View File

@ -2271,28 +2271,28 @@ ARMTargetLowering::getARMCmp(SDValue LHS, SDValue RHS, ISD::CondCode CC,
default: break;
case ISD::SETLT:
case ISD::SETGE:
if (isLegalICmpImmediate(C-1)) {
if (C != 0x80000000 && isLegalICmpImmediate(C-1)) {
CC = (CC == ISD::SETLT) ? ISD::SETLE : ISD::SETGT;
RHS = DAG.getConstant(C-1, MVT::i32);
}
break;
case ISD::SETULT:
case ISD::SETUGE:
if (C > 0 && isLegalICmpImmediate(C-1)) {
if (C != 0 && isLegalICmpImmediate(C-1)) {
CC = (CC == ISD::SETULT) ? ISD::SETULE : ISD::SETUGT;
RHS = DAG.getConstant(C-1, MVT::i32);
}
break;
case ISD::SETLE:
case ISD::SETGT:
if (isLegalICmpImmediate(C+1)) {
if (C != 0x7fffffff && isLegalICmpImmediate(C+1)) {
CC = (CC == ISD::SETLE) ? ISD::SETLT : ISD::SETGE;
RHS = DAG.getConstant(C+1, MVT::i32);
}
break;
case ISD::SETULE:
case ISD::SETUGT:
if (C < 0xffffffff && isLegalICmpImmediate(C+1)) {
if (C != 0xffffffff && isLegalICmpImmediate(C+1)) {
CC = (CC == ISD::SETULE) ? ISD::SETULT : ISD::SETUGE;
RHS = DAG.getConstant(C+1, MVT::i32);
}

14
llvm/test/CodeGen/Thumb2/thumb2-cmp.ll
View File

@ -39,3 +39,17 @@ define i1 @f5(i32 %a) {
%tmp = icmp eq i32 %a, 1114112
ret i1 %tmp
}
; Check that we don't do an invalid (a > b) --> !(a < b + 1) transform.
;
; CHECK: f6:
; CHECK-NOT: cmp.w r0, #-2147483648
; CHECK: bx lr
define i32 @f6(i32 %a) {
%tmp = icmp sgt i32 %a, 2147483647
br i1 %tmp, label %true, label %false
true:
ret i32 2
false:
ret i32 0
}