[llvm] r220314 - InstCombine: Simplify FoldICmpCstShrCst
David Majnemer
david.majnemer at gmail.com
Tue Oct 21 12:51:55 PDT 2014
Author: majnemer
Date: Tue Oct 21 14:51:55 2014
New Revision: 220314
URL: http://llvm.org/viewvc/llvm-project?rev=220314&view=rev
Log:
InstCombine: Simplify FoldICmpCstShrCst
This function was complicated by the fact that it tried to perform
canonicalizations that were already preformed by InstSimplify. Remove
this extra code and move the tests over to InstSimplify. Add asserts to
make sure our preconditions hold before we make any assumptions.
Added:
llvm/trunk/test/Transforms/InstSimplify/shr-nop.ll
Removed:
llvm/trunk/test/Transforms/InstSimplify/ashr-nop.ll
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=220314&r1=220313&r2=220314&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Tue Oct 21 14:51:55 2014
@@ -1052,69 +1052,37 @@ Instruction *InstCombiner::FoldICmpCstSh
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);
- }
+ assert(AP2 != 0 && "Handled in InstSimplify");
+ assert(!AP2.isAllOnesValue() && "Handled in InstSimplify");
+ if (!AP1)
// '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);
- }
+ if (AP1 == AP2)
return getICmp(I.ICMP_EQ, A, ConstantInt::getNullValue(A->getType()));
- }
- bool IsNegative = false;
- 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()) {
- if (AP1.slt(AP2))
- // Right-shifting won't increase the magnitude.
- return getConstant(false);
- IsNegative = true;
- }
- }
-
- if (!IsNegative && AP1.ugt(AP2))
- // Right-shifting will not increase the value.
- return getConstant(false);
+ bool IsAShr = isa<AShrOperator>(Op);
+ // If we are dealing with an arithmetic shift, both constants should agree in
+ // sign. InstSimplify's SimplifyICmpInst range analysis is supposed to catch
+ // the cases when they disagree.
+ assert((!IsAShr || (AP1.isNegative() == AP2.isNegative() && AP1.sgt(AP2))) &&
+ "Handled in InstSimplify");
// Get the distance between the highest bit that's set.
int Shift;
- if (IsNegative)
+ // Both the constants are negative, take their positive to calculate log.
+ if (IsAShr && AP1.isNegative())
// Get the ones' complement of AP2 and AP1 when computing the distance.
Shift = (~AP2).logBase2() - (~AP1).logBase2();
else
Shift = AP2.logBase2() - AP1.logBase2();
- if (IsAShr ? AP1 == AP2.ashr(Shift) : AP1 == AP2.lshr(Shift))
- return getICmp(I.ICMP_EQ, A, ConstantInt::get(A->getType(), Shift));
-
+ if (Shift > 0) {
+ if (IsAShr ? AP1 == AP2.ashr(Shift) : 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);
}
Modified: llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll?rev=220314&r1=220313&r2=220314&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll Tue Oct 21 14:51:55 2014
@@ -2,134 +2,6 @@
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) {
@@ -162,70 +34,6 @@ define i1 @ashr_ne_msb_low_second_zero(i
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) {
@@ -290,22 +98,6 @@ define i1 @exact_lshr_ne_both_equal(i8 %
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) {
@@ -322,22 +114,6 @@ define i1 @lshr_eq_opposite_msb(i8 %a) {
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) {
@@ -354,70 +130,6 @@ define i1 @lshr_ne_opposite_msb(i8 %a) {
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) {
@@ -610,22 +322,6 @@ define i1 @nonexact_ashr_ne_noexactdiv(i
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) {
@@ -642,22 +338,6 @@ define i1 @nonexact_lshr_ne_noexactlog(i
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) {
Removed: llvm/trunk/test/Transforms/InstSimplify/ashr-nop.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/ashr-nop.ll?rev=220313&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/ashr-nop.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/ashr-nop.ll (removed)
@@ -1,10 +0,0 @@
-; RUN: opt < %s -instsimplify -S | FileCheck %s
-
-; CHECK-LABEL: @foo
-; CHECK-NOT: ashr
-define i32 @foo(i32 %x) {
- %o = and i32 %x, 1
- %n = add i32 %o, -1
- %t = ashr i32 %n, 17
- ret i32 %t
-}
Added: llvm/trunk/test/Transforms/InstSimplify/shr-nop.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/shr-nop.ll?rev=220314&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/shr-nop.ll (added)
+++ llvm/trunk/test/Transforms/InstSimplify/shr-nop.ll Tue Oct 21 14:51:55 2014
@@ -0,0 +1,332 @@
+; RUN: opt < %s -instsimplify -S | FileCheck %s
+
+; CHECK-LABEL: @foo
+; CHECK: %[[and:.*]] = and i32 %x, 1
+; CHECK-NEXT: %[[add:.*]] = add i32 %[[and]], -1
+; CHECK-NEXT: ret i32 %[[add]]
+define i32 @foo(i32 %x) {
+ %o = and i32 %x, 1
+ %n = add i32 %o, -1
+ %t = ashr i32 %n, 17
+ ret i32 %t
+}
+
+; 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_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: @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: @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_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: @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: @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_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_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: @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_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_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: @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
+}
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