[llvm] r335101 - [NFC][SCEV] Add tests related to bit masking (PR37793)
Roman Lebedev via llvm-commits
llvm-commits at lists.llvm.org
Wed Jun 20 00:54:11 PDT 2018
Author: lebedevri
Date: Wed Jun 20 00:54:11 2018
New Revision: 335101
URL: http://llvm.org/viewvc/llvm-project?rev=335101&view=rev
Log:
[NFC][SCEV] Add tests related to bit masking (PR37793)
Summary:
Related to https://bugs.llvm.org/show_bug.cgi?id=37793, https://reviews.llvm.org/D46760#1127287
We'd like to do this canonicalization https://rise4fun.com/Alive/Gmc
But it is currently restricted by rL155136 / rL155362, which says:
```
// This is a constant shift of a constant shift. Be careful about hiding
// shl instructions behind bit masks. They are used to represent multiplies
// by a constant, and it is important that simple arithmetic expressions
// are still recognizable by scalar evolution.
//
// The transforms applied to shl are very similar to the transforms applied
// to mul by constant. We can be more aggressive about optimizing right
// shifts.
//
// Combinations of right and left shifts will still be optimized in
// DAGCombine where scalar evolution no longer applies.
```
I think these tests show that for *constants*, SCEV has no issues with that canonicalization.
Reviewers: mkazantsev, spatel, efriedma, sanjoy
Reviewed By: mkazantsev
Subscribers: sanjoy, javed.absar, llvm-commits, stoklund, bixia
Differential Revision: https://reviews.llvm.org/D48229
Added:
llvm/trunk/test/Analysis/ScalarEvolution/extract-highbits-sameconstmask.ll
llvm/trunk/test/Analysis/ScalarEvolution/extract-highbits-variablemask.ll
llvm/trunk/test/Analysis/ScalarEvolution/extract-lowbits-sameconstmask.ll
llvm/trunk/test/Analysis/ScalarEvolution/extract-lowbits-variablemask.ll
llvm/trunk/test/Analysis/ScalarEvolution/lshr-shl-differentconstmask.ll
llvm/trunk/test/Analysis/ScalarEvolution/shl-lshr-differentconstmask.ll
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp?rev=335101&r1=335100&r2=335101&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp Wed Jun 20 00:54:11 2018
@@ -622,11 +622,8 @@ Instruction *InstCombiner::visitShl(Bina
return BinaryOperator::CreateAnd(X, ConstantInt::get(Ty, Mask));
}
- // Be careful about hiding shl instructions behind bit masks. They are used
- // to represent multiplies by a constant, and it is important that simple
- // arithmetic expressions are still recognizable by scalar evolution.
- // The inexact versions are deferred to DAGCombine, so we don't hide shl
- // behind a bit mask.
+ // FIXME: we do not yet transform non-exact shr's. The backend (DAGCombine)
+ // needs a few fixes for the rotate pattern recognition first.
const APInt *ShOp1;
if (match(Op0, m_Exact(m_Shr(m_Value(X), m_APInt(ShOp1))))) {
unsigned ShrAmt = ShOp1->getZExtValue();
Added: llvm/trunk/test/Analysis/ScalarEvolution/extract-highbits-sameconstmask.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/extract-highbits-sameconstmask.ll?rev=335101&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/extract-highbits-sameconstmask.ll (added)
+++ llvm/trunk/test/Analysis/ScalarEvolution/extract-highbits-sameconstmask.ll Wed Jun 20 00:54:11 2018
@@ -0,0 +1,60 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
+; RUN: opt -S -analyze -scalar-evolution < %s | FileCheck %s
+
+; The obvious case.
+define i32 @div(i32 %val) nounwind {
+; CHECK-LABEL: 'div'
+; CHECK-NEXT: Classifying expressions for: @div
+; CHECK-NEXT: %tmp1 = udiv i32 %val, 16
+; CHECK-NEXT: --> (%val /u 16) U: [0,268435456) S: [0,268435456)
+; CHECK-NEXT: %tmp2 = mul i32 %tmp1, 16
+; CHECK-NEXT: --> (16 * (%val /u 16)) U: [0,-15) S: [0,-15)
+; CHECK-NEXT: Determining loop execution counts for: @div
+;
+ %tmp1 = udiv i32 %val, 16
+ %tmp2 = mul i32 %tmp1, 16
+ ret i32 %tmp2
+}
+
+define i32 @sdiv(i32 %val) nounwind {
+; CHECK-LABEL: 'sdiv'
+; CHECK-NEXT: Classifying expressions for: @sdiv
+; CHECK-NEXT: %tmp1 = sdiv i32 %val, 16
+; CHECK-NEXT: --> %tmp1 U: full-set S: [-134217728,134217728)
+; CHECK-NEXT: %tmp2 = mul i32 %tmp1, 16
+; CHECK-NEXT: --> (16 * %tmp1) U: [0,-15) S: [-2147483648,2147483633)
+; CHECK-NEXT: Determining loop execution counts for: @sdiv
+;
+ %tmp1 = sdiv i32 %val, 16
+ %tmp2 = mul i32 %tmp1, 16
+ ret i32 %tmp2
+}
+
+; Or, it could be a number of equivalent patterns with mask:
+; b) x & (-1 << nbits)
+; d) x >> nbits << nbits
+
+define i32 @mask_b(i32 %val) nounwind {
+; CHECK-LABEL: 'mask_b'
+; CHECK-NEXT: Classifying expressions for: @mask_b
+; CHECK-NEXT: %masked = and i32 %val, -16
+; CHECK-NEXT: --> (16 * (%val /u 16)) U: [0,-15) S: [0,-15)
+; CHECK-NEXT: Determining loop execution counts for: @mask_b
+;
+ %masked = and i32 %val, -16
+ ret i32 %masked
+}
+
+define i32 @mask_d(i32 %val) nounwind {
+; CHECK-LABEL: 'mask_d'
+; CHECK-NEXT: Classifying expressions for: @mask_d
+; CHECK-NEXT: %lowbitscleared = lshr i32 %val, 4
+; CHECK-NEXT: --> (%val /u 16) U: [0,268435456) S: [0,268435456)
+; CHECK-NEXT: %masked = shl i32 %lowbitscleared, 4
+; CHECK-NEXT: --> (16 * (%val /u 16)) U: [0,-15) S: [0,-15)
+; CHECK-NEXT: Determining loop execution counts for: @mask_d
+;
+ %lowbitscleared = lshr i32 %val, 4
+ %masked = shl i32 %lowbitscleared, 4
+ ret i32 %masked
+}
Added: llvm/trunk/test/Analysis/ScalarEvolution/extract-highbits-variablemask.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/extract-highbits-variablemask.ll?rev=335101&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/extract-highbits-variablemask.ll (added)
+++ llvm/trunk/test/Analysis/ScalarEvolution/extract-highbits-variablemask.ll Wed Jun 20 00:54:11 2018
@@ -0,0 +1,68 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
+; RUN: opt -S -analyze -scalar-evolution < %s | FileCheck %s
+
+; These testcases aren't *identical* but they have the same/similar meaning.
+
+; The obvious case.
+define i32 @div(i32 %val, i32 %num) nounwind {
+; CHECK-LABEL: 'div'
+; CHECK-NEXT: Classifying expressions for: @div
+; CHECK-NEXT: %tmp1 = udiv i32 %val, %num
+; CHECK-NEXT: --> (%val /u %num) U: full-set S: full-set
+; CHECK-NEXT: %tmp2 = mul i32 %tmp1, %num
+; CHECK-NEXT: --> ((%val /u %num) * %num) U: full-set S: full-set
+; CHECK-NEXT: Determining loop execution counts for: @div
+;
+ %tmp1 = udiv i32 %val, %num
+ %tmp2 = mul i32 %tmp1, %num
+ ret i32 %tmp2
+}
+
+define i32 @sdiv(i32 %val, i32 %num) nounwind {
+; CHECK-LABEL: 'sdiv'
+; CHECK-NEXT: Classifying expressions for: @sdiv
+; CHECK-NEXT: %tmp1 = sdiv i32 %val, %num
+; CHECK-NEXT: --> %tmp1 U: full-set S: full-set
+; CHECK-NEXT: %tmp2 = mul i32 %tmp1, %num
+; CHECK-NEXT: --> (%num * %tmp1) U: full-set S: full-set
+; CHECK-NEXT: Determining loop execution counts for: @sdiv
+;
+ %tmp1 = sdiv i32 %val, %num
+ %tmp2 = mul i32 %tmp1, %num
+ ret i32 %tmp2
+}
+
+; Or, it could be a number of equivalent patterns with mask:
+; b) x & (-1 << nbits)
+; d) x >> (32 - y) << (32 - y)
+
+define i32 @mask_b(i32 %val, i32 %numlowbits) nounwind {
+; CHECK-LABEL: 'mask_b'
+; CHECK-NEXT: Classifying expressions for: @mask_b
+; CHECK-NEXT: %mask = shl i32 -1, %numlowbits
+; CHECK-NEXT: --> %mask U: full-set S: full-set
+; CHECK-NEXT: %masked = and i32 %mask, %val
+; CHECK-NEXT: --> %masked U: full-set S: full-set
+; CHECK-NEXT: Determining loop execution counts for: @mask_b
+;
+ %mask = shl i32 -1, %numlowbits
+ %masked = and i32 %mask, %val
+ ret i32 %masked
+}
+
+define i32 @mask_d(i32 %val, i32 %lowbits) nounwind {
+; CHECK-LABEL: 'mask_d'
+; CHECK-NEXT: Classifying expressions for: @mask_d
+; CHECK-NEXT: %numlowbits = sub i32 32, %lowbits
+; CHECK-NEXT: --> (32 + (-1 * %lowbits)) U: full-set S: full-set
+; CHECK-NEXT: %lowbitscleared = lshr i32 %val, %numlowbits
+; CHECK-NEXT: --> %lowbitscleared U: full-set S: full-set
+; CHECK-NEXT: %masked = shl i32 %lowbitscleared, %numlowbits
+; CHECK-NEXT: --> %masked U: full-set S: full-set
+; CHECK-NEXT: Determining loop execution counts for: @mask_d
+;
+ %numlowbits = sub i32 32, %lowbits
+ %lowbitscleared = lshr i32 %val, %numlowbits
+ %masked = shl i32 %lowbitscleared, %numlowbits
+ ret i32 %masked
+}
Added: llvm/trunk/test/Analysis/ScalarEvolution/extract-lowbits-sameconstmask.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/extract-lowbits-sameconstmask.ll?rev=335101&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/extract-lowbits-sameconstmask.ll (added)
+++ llvm/trunk/test/Analysis/ScalarEvolution/extract-lowbits-sameconstmask.ll Wed Jun 20 00:54:11 2018
@@ -0,0 +1,48 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
+; RUN: opt -S -analyze -scalar-evolution < %s | FileCheck %s
+
+; The obvious case.
+define i32 @mul(i32 %val) nounwind {
+; CHECK-LABEL: 'mul'
+; CHECK-NEXT: Classifying expressions for: @mul
+; CHECK-NEXT: %tmp1 = mul i32 %val, 16
+; CHECK-NEXT: --> (16 * %val) U: [0,-15) S: [-2147483648,2147483633)
+; CHECK-NEXT: %tmp2 = udiv i32 %tmp1, 16
+; CHECK-NEXT: --> ((16 * %val) /u 16) U: [0,268435456) S: [0,268435456)
+; CHECK-NEXT: Determining loop execution counts for: @mul
+;
+ %tmp1 = mul i32 %val, 16
+ %tmp2 = udiv i32 %tmp1, 16
+ ret i32 %tmp2
+}
+
+; Or, it could be any number of equivalent patterns with mask:
+; a) x & (1 << nbits) - 1
+; b) x & ~(-1 << nbits)
+; c) x & (-1 >> (32 - y))
+; d) x << (32 - y) >> (32 - y)
+
+define i32 @mask_abc(i32 %val) nounwind {
+; CHECK-LABEL: 'mask_abc'
+; CHECK-NEXT: Classifying expressions for: @mask_abc
+; CHECK-NEXT: %masked = and i32 %val, 15
+; CHECK-NEXT: --> (zext i4 (trunc i32 %val to i4) to i32) U: [0,16) S: [0,16)
+; CHECK-NEXT: Determining loop execution counts for: @mask_abc
+;
+ %masked = and i32 %val, 15
+ ret i32 %masked
+}
+
+define i32 @mask_d(i32 %val) nounwind {
+; CHECK-LABEL: 'mask_d'
+; CHECK-NEXT: Classifying expressions for: @mask_d
+; CHECK-NEXT: %highbitscleared = shl i32 %val, 4
+; CHECK-NEXT: --> (16 * %val) U: [0,-15) S: [-2147483648,2147483633)
+; CHECK-NEXT: %masked = lshr i32 %highbitscleared, 4
+; CHECK-NEXT: --> ((16 * %val) /u 16) U: [0,268435456) S: [0,268435456)
+; CHECK-NEXT: Determining loop execution counts for: @mask_d
+;
+ %highbitscleared = shl i32 %val, 4
+ %masked = lshr i32 %highbitscleared, 4
+ ret i32 %masked
+}
Added: llvm/trunk/test/Analysis/ScalarEvolution/extract-lowbits-variablemask.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/extract-lowbits-variablemask.ll?rev=335101&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/extract-lowbits-variablemask.ll (added)
+++ llvm/trunk/test/Analysis/ScalarEvolution/extract-lowbits-variablemask.ll Wed Jun 20 00:54:11 2018
@@ -0,0 +1,93 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
+; RUN: opt -S -analyze -scalar-evolution < %s | FileCheck %s
+
+; These testcases aren't *identical* but they have the same/similar meaning.
+
+; The obvious case.
+define i32 @mul(i32 %val, i32 %num) nounwind {
+; CHECK-LABEL: 'mul'
+; CHECK-NEXT: Classifying expressions for: @mul
+; CHECK-NEXT: %tmp1 = mul i32 %val, %num
+; CHECK-NEXT: --> (%val * %num) U: full-set S: full-set
+; CHECK-NEXT: %tmp2 = udiv i32 %tmp1, %num
+; CHECK-NEXT: --> ((%val * %num) /u %num) U: full-set S: full-set
+; CHECK-NEXT: Determining loop execution counts for: @mul
+;
+ %tmp1 = mul i32 %val, %num
+ %tmp2 = udiv i32 %tmp1, %num
+ ret i32 %tmp2
+}
+
+; Or, it could be any number of equivalent patterns with mask:
+; a) x & (1 << nbits) - 1
+; b) x & ~(-1 << nbits)
+; c) x & (-1 >> (32 - y))
+; d) x << (32 - y) >> (32 - y)
+
+define i32 @mask_a(i32 %val, i32 %numlowbits) nounwind {
+; CHECK-LABEL: 'mask_a'
+; CHECK-NEXT: Classifying expressions for: @mask_a
+; CHECK-NEXT: %onebit = shl i32 1, %numlowbits
+; CHECK-NEXT: --> %onebit U: full-set S: full-set
+; CHECK-NEXT: %mask = add nsw i32 %onebit, -1
+; CHECK-NEXT: --> (-1 + %onebit) U: full-set S: full-set
+; CHECK-NEXT: %masked = and i32 %mask, %val
+; CHECK-NEXT: --> %masked U: full-set S: full-set
+; CHECK-NEXT: Determining loop execution counts for: @mask_a
+;
+ %onebit = shl i32 1, %numlowbits
+ %mask = add nsw i32 %onebit, -1
+ %masked = and i32 %mask, %val
+ ret i32 %masked
+}
+
+define i32 @mask_b(i32 %val, i32 %numlowbits) nounwind {
+; CHECK-LABEL: 'mask_b'
+; CHECK-NEXT: Classifying expressions for: @mask_b
+; CHECK-NEXT: %notmask = shl i32 -1, %numlowbits
+; CHECK-NEXT: --> %notmask U: full-set S: full-set
+; CHECK-NEXT: %mask = xor i32 %notmask, -1
+; CHECK-NEXT: --> (-1 + (-1 * %notmask)) U: full-set S: full-set
+; CHECK-NEXT: %masked = and i32 %mask, %val
+; CHECK-NEXT: --> %masked U: full-set S: full-set
+; CHECK-NEXT: Determining loop execution counts for: @mask_b
+;
+ %notmask = shl i32 -1, %numlowbits
+ %mask = xor i32 %notmask, -1
+ %masked = and i32 %mask, %val
+ ret i32 %masked
+}
+
+define i32 @mask_c(i32 %val, i32 %numlowbits) nounwind {
+; CHECK-LABEL: 'mask_c'
+; CHECK-NEXT: Classifying expressions for: @mask_c
+; CHECK-NEXT: %numhighbits = sub i32 32, %numlowbits
+; CHECK-NEXT: --> (32 + (-1 * %numlowbits)) U: full-set S: full-set
+; CHECK-NEXT: %mask = lshr i32 -1, %numhighbits
+; CHECK-NEXT: --> %mask U: full-set S: full-set
+; CHECK-NEXT: %masked = and i32 %mask, %val
+; CHECK-NEXT: --> %masked U: full-set S: full-set
+; CHECK-NEXT: Determining loop execution counts for: @mask_c
+;
+ %numhighbits = sub i32 32, %numlowbits
+ %mask = lshr i32 -1, %numhighbits
+ %masked = and i32 %mask, %val
+ ret i32 %masked
+}
+
+define i32 @mask_d(i32 %val, i32 %numlowbits) nounwind {
+; CHECK-LABEL: 'mask_d'
+; CHECK-NEXT: Classifying expressions for: @mask_d
+; CHECK-NEXT: %numhighbits = sub i32 32, %numlowbits
+; CHECK-NEXT: --> (32 + (-1 * %numlowbits)) U: full-set S: full-set
+; CHECK-NEXT: %highbitscleared = shl i32 %val, %numhighbits
+; CHECK-NEXT: --> %highbitscleared U: full-set S: full-set
+; CHECK-NEXT: %masked = lshr i32 %highbitscleared, %numhighbits
+; CHECK-NEXT: --> %masked U: full-set S: full-set
+; CHECK-NEXT: Determining loop execution counts for: @mask_d
+;
+ %numhighbits = sub i32 32, %numlowbits
+ %highbitscleared = shl i32 %val, %numhighbits
+ %masked = lshr i32 %highbitscleared, %numhighbits
+ ret i32 %masked
+}
Added: llvm/trunk/test/Analysis/ScalarEvolution/lshr-shl-differentconstmask.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/lshr-shl-differentconstmask.ll?rev=335101&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/lshr-shl-differentconstmask.ll (added)
+++ llvm/trunk/test/Analysis/ScalarEvolution/lshr-shl-differentconstmask.ll Wed Jun 20 00:54:11 2018
@@ -0,0 +1,141 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
+; RUN: opt -S -analyze -scalar-evolution < %s | FileCheck %s
+
+; The obvious case.
+define i32 @udiv_biggerLshr(i32 %val) nounwind {
+; CHECK-LABEL: 'udiv_biggerLshr'
+; CHECK-NEXT: Classifying expressions for: @udiv_biggerLshr
+; CHECK-NEXT: %tmp1 = udiv i32 %val, 64
+; CHECK-NEXT: --> (%val /u 64) U: [0,67108864) S: [0,67108864)
+; CHECK-NEXT: %tmp2 = mul i32 %tmp1, 16
+; CHECK-NEXT: --> (16 * (%val /u 64)) U: [0,1073741809) S: [0,1073741809)
+; CHECK-NEXT: Determining loop execution counts for: @udiv_biggerLshr
+;
+ %tmp1 = udiv i32 %val, 64
+ %tmp2 = mul i32 %tmp1, 16
+ ret i32 %tmp2
+}
+
+define i32 @udiv_biggerShl(i32 %val) nounwind {
+; CHECK-LABEL: 'udiv_biggerShl'
+; CHECK-NEXT: Classifying expressions for: @udiv_biggerShl
+; CHECK-NEXT: %tmp1 = udiv i32 %val, 16
+; CHECK-NEXT: --> (%val /u 16) U: [0,268435456) S: [0,268435456)
+; CHECK-NEXT: %tmp2 = mul i32 %tmp1, 64
+; CHECK-NEXT: --> (64 * (%val /u 16)) U: [0,-63) S: [-2147483648,2147483585)
+; CHECK-NEXT: Determining loop execution counts for: @udiv_biggerShl
+;
+ %tmp1 = udiv i32 %val, 16
+ %tmp2 = mul i32 %tmp1, 64
+ ret i32 %tmp2
+}
+
+; Or, it could have been transformed to shifts
+
+define i32 @shifty_biggerLshr(i32 %val) {
+; CHECK-LABEL: 'shifty_biggerLshr'
+; CHECK-NEXT: Classifying expressions for: @shifty_biggerLshr
+; CHECK-NEXT: %tmp1 = lshr i32 %val, 6
+; CHECK-NEXT: --> (%val /u 64) U: [0,67108864) S: [0,67108864)
+; CHECK-NEXT: %tmp2 = shl i32 %tmp1, 4
+; CHECK-NEXT: --> (16 * (%val /u 64)) U: [0,1073741809) S: [0,1073741809)
+; CHECK-NEXT: Determining loop execution counts for: @shifty_biggerLshr
+;
+ %tmp1 = lshr i32 %val, 6
+ %tmp2 = shl i32 %tmp1, 4
+ ret i32 %tmp2
+}
+
+define i32 @shifty_biggerLshr_lshrexact(i32 %val) {
+; CHECK-LABEL: 'shifty_biggerLshr_lshrexact'
+; CHECK-NEXT: Classifying expressions for: @shifty_biggerLshr_lshrexact
+; CHECK-NEXT: %tmp1 = lshr exact i32 %val, 6
+; CHECK-NEXT: --> (%val /u 64) U: [0,67108864) S: [0,67108864)
+; CHECK-NEXT: %tmp2 = shl i32 %tmp1, 4
+; CHECK-NEXT: --> (16 * (%val /u 64)) U: [0,1073741809) S: [0,1073741809)
+; CHECK-NEXT: Determining loop execution counts for: @shifty_biggerLshr_lshrexact
+;
+ %tmp1 = lshr exact i32 %val, 6
+ %tmp2 = shl i32 %tmp1, 4
+ ret i32 %tmp2
+}
+
+define i32 @shifty_biggerShr(i32 %val) {
+; CHECK-LABEL: 'shifty_biggerShr'
+; CHECK-NEXT: Classifying expressions for: @shifty_biggerShr
+; CHECK-NEXT: %tmp1 = lshr i32 %val, 4
+; CHECK-NEXT: --> (%val /u 16) U: [0,268435456) S: [0,268435456)
+; CHECK-NEXT: %tmp2 = shl i32 %tmp1, 6
+; CHECK-NEXT: --> (64 * (%val /u 16)) U: [0,-63) S: [-2147483648,2147483585)
+; CHECK-NEXT: Determining loop execution counts for: @shifty_biggerShr
+;
+ %tmp1 = lshr i32 %val, 4
+ %tmp2 = shl i32 %tmp1, 6
+ ret i32 %tmp2
+}
+
+define i32 @shifty_biggerShr_lshrexact(i32 %val) {
+; CHECK-LABEL: 'shifty_biggerShr_lshrexact'
+; CHECK-NEXT: Classifying expressions for: @shifty_biggerShr_lshrexact
+; CHECK-NEXT: %tmp1 = lshr exact i32 %val, 4
+; CHECK-NEXT: --> (%val /u 16) U: [0,268435456) S: [0,268435456)
+; CHECK-NEXT: %tmp2 = shl i32 %tmp1, 6
+; CHECK-NEXT: --> (64 * (%val /u 16)) U: [0,-63) S: [-2147483648,2147483585)
+; CHECK-NEXT: Determining loop execution counts for: @shifty_biggerShr_lshrexact
+;
+ %tmp1 = lshr exact i32 %val, 4
+ %tmp2 = shl i32 %tmp1, 6
+ ret i32 %tmp2
+}
+
+; Or, further folded into mask variant.
+
+define i32 @masky_biggerLshr(i32 %val) {
+; CHECK-LABEL: 'masky_biggerLshr'
+; CHECK-NEXT: Classifying expressions for: @masky_biggerLshr
+; CHECK-NEXT: %tmp1 = lshr i32 %val, 2
+; CHECK-NEXT: --> (%val /u 4) U: [0,1073741824) S: [0,1073741824)
+; CHECK-NEXT: %tmp2 = and i32 %tmp1, -16
+; CHECK-NEXT: --> (16 * (%val /u 64)) U: [0,1073741809) S: [0,1073741809)
+; CHECK-NEXT: Determining loop execution counts for: @masky_biggerLshr
+;
+ %tmp1 = lshr i32 %val, 2
+ %tmp2 = and i32 %tmp1, -16
+ ret i32 %tmp2
+}
+
+define i32 @masky_biggerLshr_lshrexact(i32 %val) {
+; CHECK-LABEL: 'masky_biggerLshr_lshrexact'
+; CHECK-NEXT: Classifying expressions for: @masky_biggerLshr_lshrexact
+; CHECK-NEXT: %tmp1 = lshr exact i32 %val, 2
+; CHECK-NEXT: --> (%val /u 4) U: [0,1073741824) S: [0,1073741824)
+; CHECK-NEXT: Determining loop execution counts for: @masky_biggerLshr_lshrexact
+;
+ %tmp1 = lshr exact i32 %val, 2
+ ret i32 %tmp1
+}
+
+define i32 @masky_biggerShr(i32 %val) {
+; CHECK-LABEL: 'masky_biggerShr'
+; CHECK-NEXT: Classifying expressions for: @masky_biggerShr
+; CHECK-NEXT: %tmp1 = shl i32 %val, 2
+; CHECK-NEXT: --> (4 * %val) U: [0,-3) S: [-2147483648,2147483645)
+; CHECK-NEXT: %tmp2 = and i32 %tmp1, -64
+; CHECK-NEXT: --> (64 * (zext i26 (trunc i32 (%val /u 16) to i26) to i32)) U: [0,-63) S: [0,-63)
+; CHECK-NEXT: Determining loop execution counts for: @masky_biggerShr
+;
+ %tmp1 = shl i32 %val, 2
+ %tmp2 = and i32 %tmp1, -64
+ ret i32 %tmp2
+}
+
+define i32 @masky_biggerShr_lshrexact(i32 %val) {
+; CHECK-LABEL: 'masky_biggerShr_lshrexact'
+; CHECK-NEXT: Classifying expressions for: @masky_biggerShr_lshrexact
+; CHECK-NEXT: %tmp1 = shl i32 %val, 2
+; CHECK-NEXT: --> (4 * %val) U: [0,-3) S: [-2147483648,2147483645)
+; CHECK-NEXT: Determining loop execution counts for: @masky_biggerShr_lshrexact
+;
+ %tmp1 = shl i32 %val, 2
+ ret i32 %tmp1
+}
Added: llvm/trunk/test/Analysis/ScalarEvolution/shl-lshr-differentconstmask.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/shl-lshr-differentconstmask.ll?rev=335101&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/shl-lshr-differentconstmask.ll (added)
+++ llvm/trunk/test/Analysis/ScalarEvolution/shl-lshr-differentconstmask.ll Wed Jun 20 00:54:11 2018
@@ -0,0 +1,141 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
+; RUN: opt -S -analyze -scalar-evolution < %s | FileCheck %s
+
+; The obvious case.
+define i32 @mul_biggerShl(i32 %val) nounwind {
+; CHECK-LABEL: 'mul_biggerShl'
+; CHECK-NEXT: Classifying expressions for: @mul_biggerShl
+; CHECK-NEXT: %tmp1 = mul i32 %val, 64
+; CHECK-NEXT: --> (64 * %val) U: [0,-63) S: [-2147483648,2147483585)
+; CHECK-NEXT: %tmp2 = udiv i32 %tmp1, 16
+; CHECK-NEXT: --> ((64 * %val) /u 16) U: [0,268435453) S: [0,268435456)
+; CHECK-NEXT: Determining loop execution counts for: @mul_biggerShl
+;
+ %tmp1 = mul i32 %val, 64
+ %tmp2 = udiv i32 %tmp1, 16
+ ret i32 %tmp2
+}
+
+define i32 @mul_biggerLshl(i32 %val) nounwind {
+; CHECK-LABEL: 'mul_biggerLshl'
+; CHECK-NEXT: Classifying expressions for: @mul_biggerLshl
+; CHECK-NEXT: %tmp1 = mul i32 %val, 16
+; CHECK-NEXT: --> (16 * %val) U: [0,-15) S: [-2147483648,2147483633)
+; CHECK-NEXT: %tmp2 = udiv i32 %tmp1, 64
+; CHECK-NEXT: --> ((16 * %val) /u 64) U: [0,67108864) S: [0,67108864)
+; CHECK-NEXT: Determining loop execution counts for: @mul_biggerLshl
+;
+ %tmp1 = mul i32 %val, 16
+ %tmp2 = udiv i32 %tmp1, 64
+ ret i32 %tmp2
+}
+
+; Or, it could have been transformed to shifts
+
+define i32 @shifty_biggerShl(i32 %val) {
+; CHECK-LABEL: 'shifty_biggerShl'
+; CHECK-NEXT: Classifying expressions for: @shifty_biggerShl
+; CHECK-NEXT: %tmp1 = shl i32 %val, 6
+; CHECK-NEXT: --> (64 * %val) U: [0,-63) S: [-2147483648,2147483585)
+; CHECK-NEXT: %tmp2 = lshr i32 %tmp1, 4
+; CHECK-NEXT: --> ((64 * %val) /u 16) U: [0,268435453) S: [0,268435456)
+; CHECK-NEXT: Determining loop execution counts for: @shifty_biggerShl
+;
+ %tmp1 = shl i32 %val, 6
+ %tmp2 = lshr i32 %tmp1, 4
+ ret i32 %tmp2
+}
+
+define i32 @shifty_biggerShl_shlnuw(i32 %val) {
+; CHECK-LABEL: 'shifty_biggerShl_shlnuw'
+; CHECK-NEXT: Classifying expressions for: @shifty_biggerShl_shlnuw
+; CHECK-NEXT: %tmp1 = shl nuw i32 %val, 6
+; CHECK-NEXT: --> (64 * %val) U: [0,-63) S: [-2147483648,2147483585)
+; CHECK-NEXT: %tmp2 = lshr i32 %tmp1, 4
+; CHECK-NEXT: --> ((64 * %val) /u 16) U: [0,268435453) S: [0,268435456)
+; CHECK-NEXT: Determining loop execution counts for: @shifty_biggerShl_shlnuw
+;
+ %tmp1 = shl nuw i32 %val, 6
+ %tmp2 = lshr i32 %tmp1, 4
+ ret i32 %tmp2
+}
+
+define i32 @shifty_biggerLshr(i32 %val) {
+; CHECK-LABEL: 'shifty_biggerLshr'
+; CHECK-NEXT: Classifying expressions for: @shifty_biggerLshr
+; CHECK-NEXT: %tmp1 = shl i32 %val, 4
+; CHECK-NEXT: --> (16 * %val) U: [0,-15) S: [-2147483648,2147483633)
+; CHECK-NEXT: %tmp2 = lshr i32 %tmp1, 6
+; CHECK-NEXT: --> ((16 * %val) /u 64) U: [0,67108864) S: [0,67108864)
+; CHECK-NEXT: Determining loop execution counts for: @shifty_biggerLshr
+;
+ %tmp1 = shl i32 %val, 4
+ %tmp2 = lshr i32 %tmp1, 6
+ ret i32 %tmp2
+}
+
+define i32 @shifty_biggerLshr_shlnuw(i32 %val) {
+; CHECK-LABEL: 'shifty_biggerLshr_shlnuw'
+; CHECK-NEXT: Classifying expressions for: @shifty_biggerLshr_shlnuw
+; CHECK-NEXT: %tmp1 = shl nuw i32 %val, 4
+; CHECK-NEXT: --> (16 * %val) U: [0,-15) S: [-2147483648,2147483633)
+; CHECK-NEXT: %tmp2 = lshr i32 %tmp1, 6
+; CHECK-NEXT: --> ((16 * %val) /u 64) U: [0,67108864) S: [0,67108864)
+; CHECK-NEXT: Determining loop execution counts for: @shifty_biggerLshr_shlnuw
+;
+ %tmp1 = shl nuw i32 %val, 4
+ %tmp2 = lshr i32 %tmp1, 6
+ ret i32 %tmp2
+}
+
+; Or, further folded into mask variant.
+
+define i32 @masky_biggerShl(i32 %val) {
+; CHECK-LABEL: 'masky_biggerShl'
+; CHECK-NEXT: Classifying expressions for: @masky_biggerShl
+; CHECK-NEXT: %tmp1 = shl i32 %val, 2
+; CHECK-NEXT: --> (4 * %val) U: [0,-3) S: [-2147483648,2147483645)
+; CHECK-NEXT: %tmp2 = and i32 %tmp1, 268435452
+; CHECK-NEXT: --> (4 * (zext i26 (trunc i32 %val to i26) to i32)) U: [0,268435453) S: [0,268435453)
+; CHECK-NEXT: Determining loop execution counts for: @masky_biggerShl
+;
+ %tmp1 = shl i32 %val, 2
+ %tmp2 = and i32 %tmp1, 268435452
+ ret i32 %tmp2
+}
+
+define i32 @masky_biggerShl_shlnuw(i32 %val) {
+; CHECK-LABEL: 'masky_biggerShl_shlnuw'
+; CHECK-NEXT: Classifying expressions for: @masky_biggerShl_shlnuw
+; CHECK-NEXT: %tmp1 = shl nuw i32 %val, 2
+; CHECK-NEXT: --> (4 * %val) U: [0,-3) S: [-2147483648,2147483645)
+; CHECK-NEXT: Determining loop execution counts for: @masky_biggerShl_shlnuw
+;
+ %tmp1 = shl nuw i32 %val, 2
+ ret i32 %tmp1
+}
+
+define i32 @masky_biggerLshr(i32 %val) {
+; CHECK-LABEL: 'masky_biggerLshr'
+; CHECK-NEXT: Classifying expressions for: @masky_biggerLshr
+; CHECK-NEXT: %tmp1 = lshr i32 %val, 2
+; CHECK-NEXT: --> (%val /u 4) U: [0,1073741824) S: [0,1073741824)
+; CHECK-NEXT: %tmp2 = and i32 %tmp1, 67108863
+; CHECK-NEXT: --> (zext i26 (trunc i32 (%val /u 4) to i26) to i32) U: [0,67108864) S: [0,67108864)
+; CHECK-NEXT: Determining loop execution counts for: @masky_biggerLshr
+;
+ %tmp1 = lshr i32 %val, 2
+ %tmp2 = and i32 %tmp1, 67108863
+ ret i32 %tmp2
+}
+
+define i32 @masky_biggerLshr_shlnuw(i32 %val) {
+; CHECK-LABEL: 'masky_biggerLshr_shlnuw'
+; CHECK-NEXT: Classifying expressions for: @masky_biggerLshr_shlnuw
+; CHECK-NEXT: %tmp1 = lshr i32 %val, 2
+; CHECK-NEXT: --> (%val /u 4) U: [0,1073741824) S: [0,1073741824)
+; CHECK-NEXT: Determining loop execution counts for: @masky_biggerLshr_shlnuw
+;
+ %tmp1 = lshr i32 %val, 2
+ ret i32 %tmp1
+}
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