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[ARM] Corrected condition in isSaturatingConditional 

Fixed a small error in an if condition to prevent usat/ssat being generated if (upper constant + 1) is not a
power of 2.
This commit is contained in:
Meera Nakrani 2020-09-15 10:14:30 +00:00
parent 2508ef014e
commit 1119bf95be
2 changed files with 13 additions and 1 deletions
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2
llvm/lib/Target/ARM/ARMISelLowering.cpp
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@ -5062,7 +5062,7 @@ static bool isSaturatingConditional(const SDValue &Op, SDValue &V,
int64_t PosVal = std::max(Val1, Val2);
int64_t NegVal = std::min(Val1, Val2);
if (!((Val1 > Val2 && isLTorLE(CC1)) || (Val1 < Val2 && isLTorLE(CC2))) &&
if (!((Val1 > Val2 && isLTorLE(CC1)) || (Val1 < Val2 && isLTorLE(CC2))) ||
!isPowerOf2_64(PosVal + 1))
return false;

12
llvm/test/CodeGen/ARM/usat.ll
View File

@ -176,6 +176,18 @@ entry:
ret i32 %saturateUp
}
; The interval is [0, k] but k+1 is not a power of 2
define i32 @no_unsigned_sat_incorrect_constant2(i32 %x) #0 {
; CHECK-LABEL: no_unsigned_sat_incorrect_constant2:
; CHECK-NOT: usat
entry:
%0 = icmp sgt i32 %x, 0
%saturateLow = select i1 %0, i32 %x, i32 0
%1 = icmp slt i32 %saturateLow, 8388609
%saturateUp = select i1 %1, i32 %saturateLow, i32 8388609
ret i32 %saturateUp
}
; The interval is not [0, k]
define i32 @no_unsigned_sat_incorrect_interval(i32 %x) #0 {
; CHECK-LABEL: no_unsigned_sat_incorrect_interval: