[llvm] r213678 - This patch implements optimization as mentioned in PR19753: Optimize comparisons with "ashr/lshr exact" of a constanst.
Suyog Sarda
suyog.sarda at samsung.com
Tue Jul 22 12:19:37 PDT 2014
Author: suyog
Date: Tue Jul 22 14:19:36 2014
New Revision: 213678
URL: http://llvm.org/viewvc/llvm-project?rev=213678&view=rev
Log:
This patch implements optimization as mentioned in PR19753: Optimize comparisons with "ashr/lshr exact" of a constanst.
It handles the errors which were seen in PR19958 where wrong code was being emitted due to earlier patch.
Added code for lshr as well as non-exact right shifts.
It implements :
(icmp eq/ne (ashr/lshr const2, A), const1)" ->
(icmp eq/ne A, Log2(const2/const1)) ->
(icmp eq/ne A, Log2(const2) - Log2(const1))
Differential Revision: http://reviews.llvm.org/D4068
Added:
llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombine.h
llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombine.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombine.h?rev=213678&r1=213677&r2=213678&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombine.h (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombine.h Tue Jul 22 14:19:36 2014
@@ -172,6 +172,8 @@ public:
ConstantInt *DivRHS);
Instruction *FoldICmpShrCst(ICmpInst &ICI, BinaryOperator *DivI,
ConstantInt *DivRHS);
+ Instruction *FoldICmpCstShrCst(ICmpInst &I, Value *Op, Value *A,
+ ConstantInt *CI1, ConstantInt *CI2);
Instruction *FoldICmpAddOpCst(Instruction &ICI, Value *X, ConstantInt *CI,
ICmpInst::Predicate Pred);
Instruction *FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=213678&r1=213677&r2=213678&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Tue Jul 22 14:19:36 2014
@@ -1044,6 +1044,90 @@ Instruction *InstCombiner::FoldICmpShrCs
return nullptr;
}
+/// FoldICmpCstShrCst - Handle "(icmp eq/ne (ashr/lshr const2, A), const1)" ->
+/// (icmp eq/ne A, Log2(const2/const1)) ->
+/// (icmp eq/ne A, Log2(const2) - Log2(const1)).
+Instruction *InstCombiner::FoldICmpCstShrCst(ICmpInst &I, Value *Op, Value *A,
+ ConstantInt *CI1,
+ ConstantInt *CI2) {
+ assert(I.isEquality() && "Cannot fold icmp gt/lt");
+
+ auto getConstant = [&I, this](bool IsTrue) {
+ if (I.getPredicate() == I.ICMP_NE)
+ IsTrue = !IsTrue;
+ return ReplaceInstUsesWith(I, ConstantInt::get(I.getType(), IsTrue));
+ };
+
+ auto getICmp = [&I](CmpInst::Predicate Pred, Value *LHS, Value *RHS) {
+ if (I.getPredicate() == I.ICMP_NE)
+ Pred = CmpInst::getInversePredicate(Pred);
+ return new ICmpInst(Pred, LHS, RHS);
+ };
+
+ APInt AP1 = CI1->getValue();
+ APInt AP2 = CI2->getValue();
+
+ if (!AP1) {
+ if (!AP2) {
+ // Both Constants are 0.
+ return getConstant(true);
+ }
+
+ if (cast<BinaryOperator>(Op)->isExact())
+ return getConstant(false);
+
+ if (AP2.isNegative()) {
+ // MSB is set, so a lshr with a large enough 'A' would be undefined.
+ return getConstant(false);
+ }
+
+ // 'A' must be large enough to shift out the highest set bit.
+ return getICmp(I.ICMP_UGT, A,
+ ConstantInt::get(A->getType(), AP2.logBase2()));
+ }
+
+ if (!AP2) {
+ // Shifting 0 by any value gives 0.
+ return getConstant(false);
+ }
+
+ bool IsAShr = isa<AShrOperator>(Op);
+ if (AP1 == AP2) {
+ if (AP1.isAllOnesValue() && IsAShr) {
+ // Arithmatic shift of -1 is always -1.
+ return getConstant(true);
+ }
+ return getICmp(I.ICMP_EQ, A, ConstantInt::getNullValue(A->getType()));
+ }
+
+ if (IsAShr) {
+ if (AP1.isNegative() != AP2.isNegative()) {
+ // Arithmetic shift will never change the sign.
+ return getConstant(false);
+ }
+ // Both the constants are negative, take their positive to calculate
+ // log.
+ if (AP1.isNegative()) {
+ AP1 = -AP1;
+ AP2 = -AP2;
+ }
+ }
+
+ if (AP1.ugt(AP2)) {
+ // Right-shifting will not increase the value.
+ return getConstant(false);
+ }
+
+ // Get the distance between the highest bit that's set.
+ int Shift = AP2.logBase2() - AP1.logBase2();
+
+ // Use lshr here, since we've canonicalized to +ve numbers.
+ if (AP1 == AP2.lshr(Shift))
+ return getICmp(I.ICMP_EQ, A, ConstantInt::get(A->getType(), Shift));
+
+ // Shifting const2 will never be equal to const1.
+ return getConstant(false);
+}
/// visitICmpInstWithInstAndIntCst - Handle "icmp (instr, intcst)".
///
@@ -2469,6 +2553,15 @@ Instruction *InstCombiner::visitICmpInst
Builder->getInt(CI->getValue()-1));
}
+ // (icmp eq/ne (ashr/lshr const2, A), const1)
+ if (I.isEquality()) {
+ ConstantInt *CI2;
+ if (match(Op0, m_AShr(m_ConstantInt(CI2), m_Value(A))) ||
+ match(Op0, m_LShr(m_ConstantInt(CI2), m_Value(A)))) {
+ return FoldICmpCstShrCst(I, Op0, A, CI, CI2);
+ }
+ }
+
// If this comparison is a normal comparison, it demands all
// bits, if it is a sign bit comparison, it only demands the sign bit.
bool UnusedBit;
Added: llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll?rev=213678&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll Tue Jul 22 14:19:36 2014
@@ -0,0 +1,677 @@
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-p:64:64:64-p1:16:16:16-p2:32:32:32-p3:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
+
+; CHECK-LABEL: @exact_lshr_eq_both_zero
+; CHECK-NEXT: ret i1 true
+define i1 @exact_lshr_eq_both_zero(i8 %a) {
+ %shr = lshr exact i8 0, %a
+ %cmp = icmp eq i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_eq_both_zero
+; CHECK-NEXT: ret i1 true
+define i1 @exact_ashr_eq_both_zero(i8 %a) {
+ %shr = ashr exact i8 0, %a
+ %cmp = icmp eq i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_lshr_eq_both_zero
+; CHECK-NEXT: ret i1 true
+define i1 @nonexact_lshr_eq_both_zero(i8 %a) {
+ %shr = lshr i8 0, %a
+ %cmp = icmp eq i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_ashr_eq_both_zero
+; CHECK-NEXT: ret i1 true
+define i1 @nonexact_ashr_eq_both_zero(i8 %a) {
+ %shr = ashr i8 0, %a
+ %cmp = icmp eq i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_ne_both_zero
+; CHECK-NEXT: ret i1 false
+define i1 @exact_lshr_ne_both_zero(i8 %a) {
+ %shr = lshr exact i8 0, %a
+ %cmp = icmp ne i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_ne_both_zero
+; CHECK-NEXT: ret i1 false
+define i1 @exact_ashr_ne_both_zero(i8 %a) {
+ %shr = ashr exact i8 0, %a
+ %cmp = icmp ne i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_lshr_ne_both_zero
+; CHECK-NEXT: ret i1 false
+define i1 @nonexact_lshr_ne_both_zero(i8 %a) {
+ %shr = lshr i8 0, %a
+ %cmp = icmp ne i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_ashr_ne_both_zero
+; CHECK-NEXT: ret i1 false
+define i1 @nonexact_ashr_ne_both_zero(i8 %a) {
+ %shr = ashr i8 0, %a
+ %cmp = icmp ne i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_eq_last_zero
+; CHECK-NEXT: ret i1 false
+define i1 @exact_lshr_eq_last_zero(i8 %a) {
+ %shr = lshr exact i8 128, %a
+ %cmp = icmp eq i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_eq_last_zero
+; CHECK-NEXT: ret i1 false
+define i1 @exact_ashr_eq_last_zero(i8 %a) {
+ %shr = ashr exact i8 -128, %a
+ %cmp = icmp eq i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_ne_last_zero
+; CHECK-NEXT: ret i1 true
+define i1 @exact_lshr_ne_last_zero(i8 %a) {
+ %shr = lshr exact i8 128, %a
+ %cmp = icmp ne i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_ne_last_zero
+; CHECK-NEXT: ret i1 true
+define i1 @exact_ashr_ne_last_zero(i8 %a) {
+ %shr = ashr exact i8 -128, %a
+ %cmp = icmp ne i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_lshr_eq_last_zero
+; CHECK-NEXT: ret i1 false
+define i1 @nonexact_lshr_eq_last_zero(i8 %a) {
+ %shr = lshr i8 128, %a
+ %cmp = icmp eq i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_ashr_eq_last_zero
+; CHECK-NEXT: ret i1 false
+define i1 @nonexact_ashr_eq_last_zero(i8 %a) {
+ %shr = ashr i8 -128, %a
+ %cmp = icmp eq i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_lshr_ne_last_zero
+; CHECK-NEXT: ret i1 true
+define i1 @nonexact_lshr_ne_last_zero(i8 %a) {
+ %shr = lshr i8 128, %a
+ %cmp = icmp ne i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_ashr_ne_last_zero
+; CHECK-NEXT: ret i1 true
+define i1 @nonexact_ashr_ne_last_zero(i8 %a) {
+ %shr = ashr i8 -128, %a
+ %cmp = icmp ne i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @lshr_eq_msb_low_last_zero
+; CHECK-NEXT: icmp ugt i8 %a, 6
+define i1 @lshr_eq_msb_low_last_zero(i8 %a) {
+ %shr = lshr i8 127, %a
+ %cmp = icmp eq i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @ashr_eq_msb_low_second_zero
+; CHECK-NEXT: icmp ugt i8 %a, 6
+define i1 @ashr_eq_msb_low_second_zero(i8 %a) {
+ %shr = ashr i8 127, %a
+ %cmp = icmp eq i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @lshr_ne_msb_low_last_zero
+; CHECK-NEXT: icmp ult i8 %a, 7
+define i1 @lshr_ne_msb_low_last_zero(i8 %a) {
+ %shr = lshr i8 127, %a
+ %cmp = icmp ne i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @ashr_ne_msb_low_second_zero
+; CHECK-NEXT: icmp ult i8 %a, 7
+define i1 @ashr_ne_msb_low_second_zero(i8 %a) {
+ %shr = ashr i8 127, %a
+ %cmp = icmp ne i8 %shr, 0
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @lshr_eq_first_zero
+; CHECK-NEXT: ret i1 false
+define i1 @lshr_eq_first_zero(i8 %a) {
+ %shr = lshr i8 0, %a
+ %cmp = icmp eq i8 %shr, 2
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @ashr_eq_first_zero
+; CHECK-NEXT: ret i1 false
+define i1 @ashr_eq_first_zero(i8 %a) {
+ %shr = ashr i8 0, %a
+ %cmp = icmp eq i8 %shr, 2
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @lshr_ne_first_zero
+; CHECK-NEXT: ret i1 true
+define i1 @lshr_ne_first_zero(i8 %a) {
+ %shr = lshr i8 0, %a
+ %cmp = icmp ne i8 %shr, 2
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @ashr_ne_first_zero
+; CHECK-NEXT: ret i1 true
+define i1 @ashr_ne_first_zero(i8 %a) {
+ %shr = ashr i8 0, %a
+ %cmp = icmp ne i8 %shr, 2
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @ashr_eq_both_minus1
+; CHECK-NEXT: ret i1 true
+define i1 @ashr_eq_both_minus1(i8 %a) {
+ %shr = ashr i8 -1, %a
+ %cmp = icmp eq i8 %shr, -1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @ashr_ne_both_minus1
+; CHECK-NEXT: ret i1 false
+define i1 @ashr_ne_both_minus1(i8 %a) {
+ %shr = ashr i8 -1, %a
+ %cmp = icmp ne i8 %shr, -1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_eq_both_minus1
+; CHECK-NEXT: ret i1 true
+define i1 @exact_ashr_eq_both_minus1(i8 %a) {
+ %shr = ashr exact i8 -1, %a
+ %cmp = icmp eq i8 %shr, -1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_ne_both_minus1
+; CHECK-NEXT: ret i1 false
+define i1 @exact_ashr_ne_both_minus1(i8 %a) {
+ %shr = ashr exact i8 -1, %a
+ %cmp = icmp ne i8 %shr, -1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @ashr_eq_both_equal
+; CHECK-NEXT: icmp eq i8 %a, 0
+define i1 @ashr_eq_both_equal(i8 %a) {
+ %shr = ashr i8 128, %a
+ %cmp = icmp eq i8 %shr, 128
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @ashr_ne_both_equal
+; CHECK-NEXT: icmp ne i8 %a, 0
+define i1 @ashr_ne_both_equal(i8 %a) {
+ %shr = ashr i8 128, %a
+ %cmp = icmp ne i8 %shr, 128
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @lshr_eq_both_equal
+; CHECK-NEXT: icmp eq i8 %a, 0
+define i1 @lshr_eq_both_equal(i8 %a) {
+ %shr = lshr i8 127, %a
+ %cmp = icmp eq i8 %shr, 127
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @lshr_ne_both_equal
+; CHECK-NEXT: icmp ne i8 %a, 0
+define i1 @lshr_ne_both_equal(i8 %a) {
+ %shr = lshr i8 127, %a
+ %cmp = icmp ne i8 %shr, 127
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_eq_both_equal
+; CHECK-NEXT: icmp eq i8 %a, 0
+define i1 @exact_ashr_eq_both_equal(i8 %a) {
+ %shr = ashr exact i8 128, %a
+ %cmp = icmp eq i8 %shr, 128
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_ne_both_equal
+; CHECK-NEXT: icmp ne i8 %a, 0
+define i1 @exact_ashr_ne_both_equal(i8 %a) {
+ %shr = ashr exact i8 128, %a
+ %cmp = icmp ne i8 %shr, 128
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_eq_both_equal
+; CHECK-NEXT: icmp eq i8 %a, 0
+define i1 @exact_lshr_eq_both_equal(i8 %a) {
+ %shr = lshr exact i8 126, %a
+ %cmp = icmp eq i8 %shr, 126
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_ne_both_equal
+; CHECK-NEXT: icmp ne i8 %a, 0
+define i1 @exact_lshr_ne_both_equal(i8 %a) {
+ %shr = lshr exact i8 126, %a
+ %cmp = icmp ne i8 %shr, 126
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_eq_opposite_msb
+; CHECK-NEXT: ret i1 false
+define i1 @exact_ashr_eq_opposite_msb(i8 %a) {
+ %shr = ashr exact i8 -128, %a
+ %cmp = icmp eq i8 %shr, 1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @ashr_eq_opposite_msb
+; CHECK-NEXT: ret i1 false
+define i1 @ashr_eq_opposite_msb(i8 %a) {
+ %shr = ashr i8 -128, %a
+ %cmp = icmp eq i8 %shr, 1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_eq_opposite_msb
+; CHECK-NEXT: icmp eq i8 %a, 7
+define i1 @exact_lshr_eq_opposite_msb(i8 %a) {
+ %shr = lshr exact i8 -128, %a
+ %cmp = icmp eq i8 %shr, 1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @lshr_eq_opposite_msb
+; CHECK-NEXT: icmp eq i8 %a, 7
+define i1 @lshr_eq_opposite_msb(i8 %a) {
+ %shr = lshr i8 -128, %a
+ %cmp = icmp eq i8 %shr, 1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_ne_opposite_msb
+; CHECK-NEXT: ret i1 true
+define i1 @exact_ashr_ne_opposite_msb(i8 %a) {
+ %shr = ashr exact i8 -128, %a
+ %cmp = icmp ne i8 %shr, 1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @ashr_ne_opposite_msb
+; CHECK-NEXT: ret i1 true
+define i1 @ashr_ne_opposite_msb(i8 %a) {
+ %shr = ashr i8 -128, %a
+ %cmp = icmp ne i8 %shr, 1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_ne_opposite_msb
+; CHECK-NEXT: icmp ne i8 %a, 7
+define i1 @exact_lshr_ne_opposite_msb(i8 %a) {
+ %shr = lshr exact i8 -128, %a
+ %cmp = icmp ne i8 %shr, 1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @lshr_ne_opposite_msb
+; CHECK-NEXT: icmp ne i8 %a, 7
+define i1 @lshr_ne_opposite_msb(i8 %a) {
+ %shr = lshr i8 -128, %a
+ %cmp = icmp ne i8 %shr, 1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_eq_shift_gt
+; CHECK-NEXT : ret i1 false
+define i1 @exact_ashr_eq_shift_gt(i8 %a) {
+ %shr = ashr exact i8 -2, %a
+ %cmp = icmp eq i8 %shr, -8
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_ne_shift_gt
+; CHECK-NEXT : ret i1 true
+define i1 @exact_ashr_ne_shift_gt(i8 %a) {
+ %shr = ashr exact i8 -2, %a
+ %cmp = icmp ne i8 %shr, -8
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_ashr_eq_shift_gt
+; CHECK-NEXT : ret i1 false
+define i1 @nonexact_ashr_eq_shift_gt(i8 %a) {
+ %shr = ashr i8 -2, %a
+ %cmp = icmp eq i8 %shr, -8
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_ashr_ne_shift_gt
+; CHECK-NEXT : ret i1 true
+define i1 @nonexact_ashr_ne_shift_gt(i8 %a) {
+ %shr = ashr i8 -2, %a
+ %cmp = icmp ne i8 %shr, -8
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_eq_shift_gt
+; CHECK-NEXT: ret i1 false
+define i1 @exact_lshr_eq_shift_gt(i8 %a) {
+ %shr = lshr exact i8 2, %a
+ %cmp = icmp eq i8 %shr, 8
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_ne_shift_gt
+; CHECK-NEXT: ret i1 true
+define i1 @exact_lshr_ne_shift_gt(i8 %a) {
+ %shr = lshr exact i8 2, %a
+ %cmp = icmp ne i8 %shr, 8
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_lshr_eq_shift_gt
+; CHECK-NEXT : ret i1 false
+define i1 @nonexact_lshr_eq_shift_gt(i8 %a) {
+ %shr = lshr i8 2, %a
+ %cmp = icmp eq i8 %shr, 8
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_lshr_ne_shift_gt
+; CHECK-NEXT : ret i1 true
+define i1 @nonexact_lshr_ne_shift_gt(i8 %a) {
+ %shr = ashr i8 2, %a
+ %cmp = icmp ne i8 %shr, 8
+ ret i1 %cmp
+}
+
+
+
+; CHECK-LABEL: @exact_ashr_eq
+; CHECK-NEXT: icmp eq i8 %a, 7
+define i1 @exact_ashr_eq(i8 %a) {
+ %shr = ashr exact i8 -128, %a
+ %cmp = icmp eq i8 %shr, -1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_ne
+; CHECK-NEXT: icmp ne i8 %a, 7
+define i1 @exact_ashr_ne(i8 %a) {
+ %shr = ashr exact i8 -128, %a
+ %cmp = icmp ne i8 %shr, -1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_eq
+; CHECK-NEXT: icmp eq i8 %a, 2
+define i1 @exact_lshr_eq(i8 %a) {
+ %shr = lshr exact i8 4, %a
+ %cmp = icmp eq i8 %shr, 1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_ne
+; CHECK-NEXT: icmp ne i8 %a, 2
+define i1 @exact_lshr_ne(i8 %a) {
+ %shr = lshr exact i8 4, %a
+ %cmp = icmp ne i8 %shr, 1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_ashr_eq
+; CHECK-NEXT: icmp eq i8 %a, 7
+define i1 @nonexact_ashr_eq(i8 %a) {
+ %shr = ashr i8 -128, %a
+ %cmp = icmp eq i8 %shr, -1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_ashr_ne
+; CHECK-NEXT: icmp ne i8 %a, 7
+define i1 @nonexact_ashr_ne(i8 %a) {
+ %shr = ashr i8 -128, %a
+ %cmp = icmp ne i8 %shr, -1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_lshr_eq
+; CHECK-NEXT: icmp eq i8 %a, 2
+define i1 @nonexact_lshr_eq(i8 %a) {
+ %shr = lshr i8 4, %a
+ %cmp = icmp eq i8 %shr, 1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_lshr_ne
+; CHECK-NEXT: icmp ne i8 %a, 2
+define i1 @nonexact_lshr_ne(i8 %a) {
+ %shr = lshr i8 4, %a
+ %cmp = icmp ne i8 %shr, 1
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_eq_exactdiv
+; CHECK-NEXT: icmp eq i8 %a, 4
+define i1 @exact_lshr_eq_exactdiv(i8 %a) {
+ %shr = lshr exact i8 80, %a
+ %cmp = icmp eq i8 %shr, 5
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_ne_exactdiv
+; CHECK-NEXT: icmp ne i8 %a, 4
+define i1 @exact_lshr_ne_exactdiv(i8 %a) {
+ %shr = lshr exact i8 80, %a
+ %cmp = icmp ne i8 %shr, 5
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_lshr_eq_exactdiv
+; CHECK-NEXT: icmp eq i8 %a, 4
+define i1 @nonexact_lshr_eq_exactdiv(i8 %a) {
+ %shr = lshr i8 80, %a
+ %cmp = icmp eq i8 %shr, 5
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_lshr_ne_exactdiv
+; CHECK-NEXT: icmp ne i8 %a, 4
+define i1 @nonexact_lshr_ne_exactdiv(i8 %a) {
+ %shr = lshr i8 80, %a
+ %cmp = icmp ne i8 %shr, 5
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_eq_exactdiv
+; CHECK-NEXT: icmp eq i8 %a, 4
+define i1 @exact_ashr_eq_exactdiv(i8 %a) {
+ %shr = ashr exact i8 -80, %a
+ %cmp = icmp eq i8 %shr, -5
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_ne_exactdiv
+; CHECK-NEXT: icmp ne i8 %a, 4
+define i1 @exact_ashr_ne_exactdiv(i8 %a) {
+ %shr = ashr exact i8 -80, %a
+ %cmp = icmp ne i8 %shr, -5
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_ashr_eq_exactdiv
+; CHECK-NEXT: icmp eq i8 %a, 4
+define i1 @nonexact_ashr_eq_exactdiv(i8 %a) {
+ %shr = ashr i8 -80, %a
+ %cmp = icmp eq i8 %shr, -5
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_ashr_ne_exactdiv
+; CHECK-NEXT: icmp ne i8 %a, 4
+define i1 @nonexact_ashr_ne_exactdiv(i8 %a) {
+ %shr = ashr i8 -80, %a
+ %cmp = icmp ne i8 %shr, -5
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_eq_noexactdiv
+; CHECK-NEXT: ret i1 false
+define i1 @exact_lshr_eq_noexactdiv(i8 %a) {
+ %shr = lshr exact i8 80, %a
+ %cmp = icmp eq i8 %shr, 31
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_ne_noexactdiv
+; CHECK-NEXT: ret i1 true
+define i1 @exact_lshr_ne_noexactdiv(i8 %a) {
+ %shr = lshr exact i8 80, %a
+ %cmp = icmp ne i8 %shr, 31
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_lshr_eq_noexactdiv
+; CHECK-NEXT: ret i1 false
+define i1 @nonexact_lshr_eq_noexactdiv(i8 %a) {
+ %shr = lshr i8 80, %a
+ %cmp = icmp eq i8 %shr, 31
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_lshr_ne_noexactdiv
+; CHECK-NEXT: ret i1 true
+define i1 @nonexact_lshr_ne_noexactdiv(i8 %a) {
+ %shr = lshr i8 80, %a
+ %cmp = icmp ne i8 %shr, 31
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_eq_noexactdiv
+; CHECK-NEXT: ret i1 false
+define i1 @exact_ashr_eq_noexactdiv(i8 %a) {
+ %shr = ashr exact i8 -80, %a
+ %cmp = icmp eq i8 %shr, -31
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_ne_noexactdiv
+; CHECK-NEXT: ret i1 true
+define i1 @exact_ashr_ne_noexactdiv(i8 %a) {
+ %shr = ashr exact i8 -80, %a
+ %cmp = icmp ne i8 %shr, -31
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_ashr_eq_noexactdiv
+; CHECK-NEXT: ret i1 false
+define i1 @nonexact_ashr_eq_noexactdiv(i8 %a) {
+ %shr = ashr i8 -80, %a
+ %cmp = icmp eq i8 %shr, -31
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_ashr_ne_noexactdiv
+; CHECK-NEXT: ret i1 true
+define i1 @nonexact_ashr_ne_noexactdiv(i8 %a) {
+ %shr = ashr i8 -80, %a
+ %cmp = icmp ne i8 %shr, -31
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_eq_noexactlog
+; CHECK-NEXT: ret i1 false
+define i1 @exact_lshr_eq_noexactlog(i8 %a) {
+ %shr = lshr exact i8 90, %a
+ %cmp = icmp eq i8 %shr, 30
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_lshr_ne_noexactlog
+; CHECK-NEXT: ret i1 true
+define i1 @exact_lshr_ne_noexactlog(i8 %a) {
+ %shr = lshr exact i8 90, %a
+ %cmp = icmp ne i8 %shr, 30
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_lshr_eq_noexactlog
+; CHECK-NEXT: ret i1 false
+define i1 @nonexact_lshr_eq_noexactlog(i8 %a) {
+ %shr = lshr i8 90, %a
+ %cmp = icmp eq i8 %shr, 30
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_lshr_ne_noexactlog
+; CHECK-NEXT: ret i1 true
+define i1 @nonexact_lshr_ne_noexactlog(i8 %a) {
+ %shr = lshr i8 90, %a
+ %cmp = icmp ne i8 %shr, 30
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_eq_noexactlog
+; CHECK-NEXT: ret i1 false
+define i1 @exact_ashr_eq_noexactlog(i8 %a) {
+ %shr = ashr exact i8 -90, %a
+ %cmp = icmp eq i8 %shr, -30
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @exact_ashr_ne_noexactlog
+; CHECK-NEXT: ret i1 true
+define i1 @exact_ashr_ne_noexactlog(i8 %a) {
+ %shr = ashr exact i8 -90, %a
+ %cmp = icmp ne i8 %shr, -30
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_ashr_eq_noexactlog
+; CHECK-NEXT: ret i1 false
+define i1 @nonexact_ashr_eq_noexactlog(i8 %a) {
+ %shr = ashr i8 -90, %a
+ %cmp = icmp eq i8 %shr, -30
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @nonexact_ashr_ne_noexactlog
+; CHECK-NEXT: ret i1 true
+define i1 @nonexact_ashr_ne_noexactlog(i8 %a) {
+ %shr = ashr i8 -90, %a
+ %cmp = icmp ne i8 %shr, -30
+ ret i1 %cmp
+}
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