[InstCombine] Teach foldOrOfICmps to allow icmp eq MIN_INT/MAX to be part of a range comparision. Similar for foldAndOfICmps
We can treat icmp eq X, MIN_UINT as icmp ule X, MIN_UINT and allow
it to merge with icmp ugt X, C. Similar for the other constants.
We can do simliar for icmp ne X, (U)INT_MIN/MAX in foldAndOfICmps. And we already handled UINT_MIN there.
Fixes PR42691.
Differential Revision: https://reviews.llvm.org/D65017
llvm-svn: 366945
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 9db0824..68cd424 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1197,7 +1197,7 @@
// (X != 13 & X u< 14) -> X < 13
if (LHSC->getValue() == (RHSC->getValue() - 1))
return Builder.CreateICmpULT(LHS0, LHSC);
- if (LHSC->isZero()) // (X != 0 & X u< 14) -> X-1 u< 13
+ if (LHSC->isZero()) // (X != 0 & X u< C) -> X-1 u< C-1
return insertRangeTest(LHS0, LHSC->getValue() + 1, RHSC->getValue(),
false, true);
break; // (X != 13 & X u< 15) -> no change
@@ -1205,7 +1205,11 @@
// (X != 13 & X s< 14) -> X < 13
if (LHSC->getValue() == (RHSC->getValue() - 1))
return Builder.CreateICmpSLT(LHS0, LHSC);
- break; // (X != 13 & X s< 15) -> no change
+ // (X != INT_MIN & X s< C) -> X-(INT_MIN+1) u< (C-(INT_MIN+1))
+ if (LHSC->isMinValue(true))
+ return insertRangeTest(LHS0, LHSC->getValue() + 1, RHSC->getValue(),
+ true, true);
+ break; // (X != 13 & X s< 15) -> no change
case ICmpInst::ICMP_NE:
// Potential folds for this case should already be handled.
break;
@@ -1219,8 +1223,12 @@
// (X u> 13 & X != 14) -> X u> 14
if (RHSC->getValue() == (LHSC->getValue() + 1))
return Builder.CreateICmp(PredL, LHS0, RHSC);
+ // X u> C & X != UINT_MAX -> (X-(C+1)) u< UINT_MAX-(C+1)
+ if (RHSC->isMaxValue(false))
+ return insertRangeTest(LHS0, LHSC->getValue() + 1, RHSC->getValue(),
+ false, true);
break; // (X u> 13 & X != 15) -> no change
- case ICmpInst::ICMP_ULT: // (X u> 13 & X u< 15) -> (X-14) <u 1
+ case ICmpInst::ICMP_ULT: // (X u> 13 & X u< 15) -> (X-14) u< 1
return insertRangeTest(LHS0, LHSC->getValue() + 1, RHSC->getValue(),
false, true);
}
@@ -1233,8 +1241,12 @@
// (X s> 13 & X != 14) -> X s> 14
if (RHSC->getValue() == (LHSC->getValue() + 1))
return Builder.CreateICmp(PredL, LHS0, RHSC);
+ // X s> C & X != INT_MAX -> (X-(C+1)) u< INT_MAX-(C+1)
+ if (RHSC->isMaxValue(true))
+ return insertRangeTest(LHS0, LHSC->getValue() + 1, RHSC->getValue(),
+ true, true);
break; // (X s> 13 & X != 15) -> no change
- case ICmpInst::ICMP_SLT: // (X s> 13 & X s< 15) -> (X-14) s< 1
+ case ICmpInst::ICMP_SLT: // (X s> 13 & X s< 15) -> (X-14) u< 1
return insertRangeTest(LHS0, LHSC->getValue() + 1, RHSC->getValue(), true,
true);
}
@@ -2253,8 +2265,19 @@
case ICmpInst::ICMP_EQ:
// Potential folds for this case should already be handled.
break;
- case ICmpInst::ICMP_UGT: // (X == 13 | X u> 14) -> no change
- case ICmpInst::ICMP_SGT: // (X == 13 | X s> 14) -> no change
+ case ICmpInst::ICMP_UGT:
+ // (X == 0 || X u> C) -> (X-1) u>= C
+ if (LHSC->isMinValue(false))
+ return insertRangeTest(LHS0, LHSC->getValue() + 1, RHSC->getValue() + 1,
+ false, false);
+ // (X == 13 | X u> 14) -> no change
+ break;
+ case ICmpInst::ICMP_SGT:
+ // (X == INT_MIN || X s> C) -> (X-(INT_MIN+1)) u>= C-INT_MIN
+ if (LHSC->isMinValue(true))
+ return insertRangeTest(LHS0, LHSC->getValue() + 1, RHSC->getValue() + 1,
+ true, false);
+ // (X == 13 | X s> 14) -> no change
break;
}
break;
@@ -2263,6 +2286,10 @@
default:
llvm_unreachable("Unknown integer condition code!");
case ICmpInst::ICMP_EQ: // (X u< 13 | X == 14) -> no change
+ // (X u< C || X == UINT_MAX) => (X-C) u>= UINT_MAX-C
+ if (RHSC->isMaxValue(false))
+ return insertRangeTest(LHS0, LHSC->getValue(), RHSC->getValue(),
+ false, false);
break;
case ICmpInst::ICMP_UGT: // (X u< 13 | X u> 15) -> (X-13) u> 2
assert(!RHSC->isMaxValue(false) && "Missed icmp simplification");
@@ -2274,9 +2301,14 @@
switch (PredR) {
default:
llvm_unreachable("Unknown integer condition code!");
- case ICmpInst::ICMP_EQ: // (X s< 13 | X == 14) -> no change
+ case ICmpInst::ICMP_EQ:
+ // (X s< C || X == INT_MAX) => (X-C) u>= INT_MAX-C
+ if (RHSC->isMaxValue(true))
+ return insertRangeTest(LHS0, LHSC->getValue(), RHSC->getValue(),
+ true, false);
+ // (X s< 13 | X == 14) -> no change
break;
- case ICmpInst::ICMP_SGT: // (X s< 13 | X s> 15) -> (X-13) s> 2
+ case ICmpInst::ICMP_SGT: // (X s< 13 | X s> 15) -> (X-13) u> 2
assert(!RHSC->isMaxValue(true) && "Missed icmp simplification");
return insertRangeTest(LHS0, LHSC->getValue(), RHSC->getValue() + 1, true,
false);