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Differential D91725

[LoopIdiom] 'left-shift until bittest' idiom: support constant bit mask
ClosedPublic

Authored by lebedev.ri on Nov 18 2020, 10:28 AM.

Details

Reviewers
craig.topper
fhahn
jdoerfert
Commits
rGcb2e5980bae3: [LoopIdiom] 'left-shift until bittest' idiom: support constant bit mask
Summary

The handing of the case where the mask is a constant is trivial,
if said constant is a power of two, the bit in question is log2(mask),
rest just works.

Diff Detail

Unit TestsFailed

TimeTest
110 msx64 windows > LLVM.CodeGen/XCore::threads.ll

Event Timeline

lebedev.ri created this revision.Nov 18 2020, 10:28 AM
Herald added a subscriber: hiraditya. · View Herald TranscriptNov 18 2020, 10:28 AM
lebedev.ri requested review of this revision.Nov 18 2020, 10:28 AM
lebedev.ri added a child revision: D91726: [LoopIdiom] 'left-shift until bittest' idiom: support canonical sign bit mask.
Harbormaster completed remote builds in B79323: Diff 306148.Nov 18 2020, 10:29 AM
lebedev.ri updated this revision to Diff 306166.Nov 18 2020, 11:18 AM

Do recurrence analysis afterwards, not when matching backedge condition.

Harbormaster completed remote builds in B79331: Diff 306166.Nov 18 2020, 11:18 AM
lebedev.ri added a parent revision: D91038: [LoopIdiom] Introduce 'left-shift until bittest' idiom.Dec 7 2020, 4:29 AM
lebedev.ri updated this revision to Diff 309875.Dec 7 2020, 4:40 AM

Rebased, NFC.

Harbormaster completed remote builds in B81276: Diff 309875.Dec 7 2020, 6:00 AM
lebedev.ri updated this revision to Diff 311685.Dec 14 2020, 1:27 PM

Rebased, NFC.

Harbormaster completed remote builds in B82327: Diff 311685.Dec 14 2020, 2:07 PM
lebedev.ri updated this revision to Diff 311818.Dec 15 2020, 12:31 AM

Rebased, NFC.

Harbormaster completed remote builds in B82413: Diff 311818.Dec 15 2020, 12:33 AM
lebedev.ri mentioned this in D91038: [LoopIdiom] Introduce 'left-shift until bittest' idiom.Dec 18 2020, 1:09 PM
craig.topper accepted this revision.Dec 23 2020, 9:39 AM

LGTM

This revision is now accepted and ready to land.Dec 23 2020, 9:39 AM
lebedev.ri added a comment.Dec 23 2020, 9:59 AM
In D91725#2470186, @craig.topper wrote:

LGTM

Thank you for the review!

lebedev.ri updated this revision to Diff 313578.Dec 23 2020, 11:25 AM

Rebased, NFC.

This revision was landed with ongoing or failed builds.Dec 23 2020, 11:28 AM
Closed by commit rGcb2e5980bae3: [LoopIdiom] 'left-shift until bittest' idiom: support constant bit mask (authored by lebedev.ri). · Explain Why
This revision was automatically updated to reflect the committed changes.
lebedev.ri added a commit: rGcb2e5980bae3: [LoopIdiom] 'left-shift until bittest' idiom: support constant bit mask.
Harbormaster completed remote builds in B83412: Diff 313578.Dec 23 2020, 12:34 PM

Revision Contents

PathSize
llvm/
lib/
Transforms/
Scalar/
9 lines
test/
Transforms/
LoopIdiom/
X86/
179 lines

Diff 309875

llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp

Show First 20 Lines • Show All 2,036 Lines • ▼ Show 20 Lines auto MatchVariableBitMask = [&]() {
return ICmpInst::isEquality(Pred) && match(CmpRHS, m_Zero()) && return ICmpInst::isEquality(Pred) && match(CmpRHS, m_Zero()) &&
match(CmpLHS, match(CmpLHS,
m_c_And(m_Value(CurrX), m_c_And(m_Value(CurrX),
m_CombineAnd( m_CombineAnd(
m_Value(BitMask), m_Value(BitMask),
m_LoopInvariant(m_Shl(m_One(), m_Value(BitPos)), m_LoopInvariant(m_Shl(m_One(), m_Value(BitPos)),
CurLoop)))); CurLoop))));
}; };
auto MatchConstantBitMask = [&]() {
return ICmpInst::isEquality(Pred) && match(CmpRHS, m_Zero()) &&
match(CmpLHS, m_And(m_Value(CurrX),
m_CombineAnd(m_Value(BitMask), m_Power2()))) &&
(BitPos = ConstantExpr::getExactLogBase2(cast<Constant>(BitMask)));
};
if (!MatchVariableBitMask()) { if (!MatchVariableBitMask() && !MatchConstantBitMask()) {
// FIXME: support constant bit mask.
// FIXME: support sign bit test (use llvm::decomposeBitTestICmp()). // FIXME: support sign bit test (use llvm::decomposeBitTestICmp()).
LLVM_DEBUG(dbgs() << DEBUG_TYPE " Bad backedge comparison.\n"); LLVM_DEBUG(dbgs() << DEBUG_TYPE " Bad backedge comparison.\n");
return false; return false;
} }
// Step 3: Check if the recurrence is in desirable form. // Step 3: Check if the recurrence is in desirable form.
if (!match( if (!match(
CurrX, CurrX,
▲ Show 20 Lines • Show All 199 Lines • Show Last 20 Lines

llvm/test/Transforms/LoopIdiom/X86/left-shift-until-bittest.ll

Show First 20 Lines • Show All 142 Lines • ▼ Show 20 Linesloop:
%x.next = shl i16 %x.curr, 1 %x.next = shl i16 %x.curr, 1
br i1 %x.curr.isbitunset, label %loop, label %end br i1 %x.curr.isbitunset, label %loop, label %end
end: end:
ret i16 %x.curr ret i16 %x.curr
} }
define i32 @p2_constant_mask_24thbit(i32 %x) { define i32 @p2_constant_mask_24thbit(i32 %x) {
; ALL-LABEL: @p2_constant_mask_24thbit( ; LZCNT-LABEL: @p2_constant_mask_24thbit(
; ALL-NEXT: entry: ; LZCNT-NEXT: entry:
; ALL-NEXT: br label [[LOOP:%.*]], [[DBG46:!dbg !.*]] ; LZCNT-NEXT: [[X_MASKED:%.*]] = and i32 [[X:%.*]], 33554431, [[DBG46:!dbg !.*]]
; ALL: loop: ; LZCNT-NEXT: [[X_MASKED_NUMLEADINGZEROS:%.*]] = call i32 @llvm.ctlz.i32(i32 [[X_MASKED]], i1 true), [[DBG46]]
; ALL-NEXT: [[X_CURR:%.*]] = phi i32 [ [[X:%.*]], [[ENTRY:%.*]] ], [ [[X_NEXT:%.*]], [[LOOP]] ], [[DBG47:!dbg !.*]] ; LZCNT-NEXT: [[X_MASKED_NUMACTIVEBITS:%.*]] = sub i32 32, [[X_MASKED_NUMLEADINGZEROS]], [[DBG46]]
; ALL-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR]], [[META42:metadata !.*]], metadata !DIExpression()), [[DBG47]] ; LZCNT-NEXT: [[X_MASKED_NUMLEADINGONEPOS:%.*]] = add i32 [[X_MASKED_NUMACTIVEBITS]], -1, [[DBG46]]
; ALL-NEXT: [[X_CURR_BITMASKED:%.*]] = and i32 [[X_CURR]], 16777216, [[DBG48:!dbg !.*]] ; LZCNT-NEXT: [[LOOP_BACKEDGETAKENCOUNT:%.*]] = sub i32 24, [[X_MASKED_NUMLEADINGONEPOS]], [[DBG46]]
; ALL-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_BITMASKED]], [[META43:metadata !.*]], metadata !DIExpression()), [[DBG48]] ; LZCNT-NEXT: [[LOOP_TRIPCOUNT:%.*]] = add nuw i32 [[LOOP_BACKEDGETAKENCOUNT]], 1, [[DBG46]]
; ALL-NEXT: [[X_CURR_ISBITUNSET:%.*]] = icmp eq i32 [[X_CURR_BITMASKED]], 0, [[DBG49:!dbg !.*]] ; LZCNT-NEXT: [[X_CURR:%.*]] = shl i32 [[X]], [[LOOP_BACKEDGETAKENCOUNT]], [[DBG46]]
; ALL-NEXT: call void @llvm.dbg.value(metadata i1 [[X_CURR_ISBITUNSET]], [[META44:metadata !.*]], metadata !DIExpression()), [[DBG49]] ; LZCNT-NEXT: [[X_NEXT:%.*]] = shl i32 [[X]], [[LOOP_TRIPCOUNT]], [[DBG46]]
; ALL-NEXT: [[X_NEXT]] = shl i32 [[X_CURR]], 1, [[DBG50:!dbg !.*]] ; LZCNT-NEXT: br label [[LOOP:%.*]], [[DBG47:!dbg !.*]]
; ALL-NEXT: call void @llvm.dbg.value(metadata i32 [[X_NEXT]], [[META45:metadata !.*]], metadata !DIExpression()), [[DBG50]] ; LZCNT: loop:
; ALL-NEXT: br i1 [[X_CURR_ISBITUNSET]], label [[LOOP]], label [[END:%.*]], [[DBG51:!dbg !.*]] ; LZCNT-NEXT: [[TMP0:%.*]] = phi i32 [ [[X]], [[ENTRY:%.*]] ], [ [[X_NEXT]], [[LOOP]] ], [[DBG46]]
; ALL: end: ; LZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR]], [[META42:metadata !.*]], metadata !DIExpression()), [[DBG46]]
; ALL-NEXT: [[X_CURR_LCSSA:%.*]] = phi i32 [ [[X_CURR]], [[LOOP]] ], [[DBG47]] ; LZCNT-NEXT: [[X_CURR_BITMASKED:%.*]] = and i32 [[X_CURR]], 16777216, [[DBG48:!dbg !.*]]
; ALL-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_LCSSA]], [[META42]], metadata !DIExpression()), [[DBG47]] ; LZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_BITMASKED]], [[META43:metadata !.*]], metadata !DIExpression()), [[DBG48]]
; ALL-NEXT: ret i32 [[X_CURR_LCSSA]], [[DBG52:!dbg !.*]] ; LZCNT-NEXT: [[X_CURR_ISBITUNSET:%.*]] = icmp eq i32 [[X_CURR_BITMASKED]], 0, [[DBG49:!dbg !.*]]
; LZCNT-NEXT: call void @llvm.dbg.value(metadata i1 [[X_CURR_ISBITUNSET]], [[META44:metadata !.*]], metadata !DIExpression()), [[DBG49]]
; LZCNT-NEXT: [[TMP1:%.*]] = shl i32 [[X_CURR]], 1, [[DBG50:!dbg !.*]]
; LZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_NEXT]], [[META45:metadata !.*]], metadata !DIExpression()), [[DBG50]]
; LZCNT-NEXT: br i1 true, label [[END:%.*]], label [[LOOP]], [[DBG51:!dbg !.*]]
; LZCNT: end:
; LZCNT-NEXT: [[X_CURR_LCSSA:%.*]] = phi i32 [ [[X_CURR]], [[LOOP]] ], [[DBG46]]
; LZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_LCSSA]], [[META42]], metadata !DIExpression()), [[DBG46]]
; LZCNT-NEXT: ret i32 [[X_CURR_LCSSA]], [[DBG52:!dbg !.*]]
;
; NOLZCNT-LABEL: @p2_constant_mask_24thbit(
; NOLZCNT-NEXT: entry:
; NOLZCNT-NEXT: br label [[LOOP:%.*]], [[DBG46:!dbg !.*]]
; NOLZCNT: loop:
; NOLZCNT-NEXT: [[X_CURR:%.*]] = phi i32 [ [[X:%.*]], [[ENTRY:%.*]] ], [ [[X_NEXT:%.*]], [[LOOP]] ], [[DBG47:!dbg !.*]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR]], [[META42:metadata !.*]], metadata !DIExpression()), [[DBG47]]
; NOLZCNT-NEXT: [[X_CURR_BITMASKED:%.*]] = and i32 [[X_CURR]], 16777216, [[DBG48:!dbg !.*]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_BITMASKED]], [[META43:metadata !.*]], metadata !DIExpression()), [[DBG48]]
; NOLZCNT-NEXT: [[X_CURR_ISBITUNSET:%.*]] = icmp eq i32 [[X_CURR_BITMASKED]], 0, [[DBG49:!dbg !.*]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i1 [[X_CURR_ISBITUNSET]], [[META44:metadata !.*]], metadata !DIExpression()), [[DBG49]]
; NOLZCNT-NEXT: [[X_NEXT]] = shl i32 [[X_CURR]], 1, [[DBG50:!dbg !.*]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_NEXT]], [[META45:metadata !.*]], metadata !DIExpression()), [[DBG50]]
; NOLZCNT-NEXT: br i1 [[X_CURR_ISBITUNSET]], label [[LOOP]], label [[END:%.*]], [[DBG51:!dbg !.*]]
; NOLZCNT: end:
; NOLZCNT-NEXT: [[X_CURR_LCSSA:%.*]] = phi i32 [ [[X_CURR]], [[LOOP]] ], [[DBG47]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_LCSSA]], [[META42]], metadata !DIExpression()), [[DBG47]]
; NOLZCNT-NEXT: ret i32 [[X_CURR_LCSSA]], [[DBG52:!dbg !.*]]
; ;
entry: entry:
br label %loop br label %loop
loop: loop:
%x.curr = phi i32 [ %x, %entry ], [ %x.next, %loop ] %x.curr = phi i32 [ %x, %entry ], [ %x.next, %loop ]
%x.curr.bitmasked = and i32 %x.curr, 16777216 %x.curr.bitmasked = and i32 %x.curr, 16777216
%x.curr.isbitunset = icmp eq i32 %x.curr.bitmasked, 0 %x.curr.isbitunset = icmp eq i32 %x.curr.bitmasked, 0
%x.next = shl i32 %x.curr, 1 %x.next = shl i32 %x.curr, 1
br i1 %x.curr.isbitunset, label %loop, label %end br i1 %x.curr.isbitunset, label %loop, label %end
end: end:
ret i32 %x.curr ret i32 %x.curr
} }
define i32 @p3_constant_mask_15thbit(i32 %x) { define i32 @p3_constant_mask_15thbit(i32 %x) {
; ALL-LABEL: @p3_constant_mask_15thbit( ; LZCNT-LABEL: @p3_constant_mask_15thbit(
; ALL-NEXT: entry: ; LZCNT-NEXT: entry:
; ALL-NEXT: br label [[LOOP:%.*]], [[DBG59:!dbg !.*]] ; LZCNT-NEXT: [[X_MASKED:%.*]] = and i32 [[X:%.*]], 65535, [[DBG59:!dbg !.*]]
; ALL: loop: ; LZCNT-NEXT: [[X_MASKED_NUMLEADINGZEROS:%.*]] = call i32 @llvm.ctlz.i32(i32 [[X_MASKED]], i1 true), [[DBG59]]
; ALL-NEXT: [[X_CURR:%.*]] = phi i32 [ [[X:%.*]], [[ENTRY:%.*]] ], [ [[X_NEXT:%.*]], [[LOOP]] ], [[DBG60:!dbg !.*]] ; LZCNT-NEXT: [[X_MASKED_NUMACTIVEBITS:%.*]] = sub i32 32, [[X_MASKED_NUMLEADINGZEROS]], [[DBG59]]
; ALL-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR]], [[META55:metadata !.*]], metadata !DIExpression()), [[DBG60]] ; LZCNT-NEXT: [[X_MASKED_NUMLEADINGONEPOS:%.*]] = add i32 [[X_MASKED_NUMACTIVEBITS]], -1, [[DBG59]]
; ALL-NEXT: [[X_CURR_BITMASKED:%.*]] = and i32 [[X_CURR]], 32768, [[DBG61:!dbg !.*]] ; LZCNT-NEXT: [[LOOP_BACKEDGETAKENCOUNT:%.*]] = sub i32 15, [[X_MASKED_NUMLEADINGONEPOS]], [[DBG59]]
; ALL-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_BITMASKED]], [[META56:metadata !.*]], metadata !DIExpression()), [[DBG61]] ; LZCNT-NEXT: [[LOOP_TRIPCOUNT:%.*]] = add nuw i32 [[LOOP_BACKEDGETAKENCOUNT]], 1, [[DBG59]]
; ALL-NEXT: [[X_CURR_ISBITUNSET:%.*]] = icmp eq i32 [[X_CURR_BITMASKED]], 0, [[DBG62:!dbg !.*]] ; LZCNT-NEXT: [[X_CURR:%.*]] = shl i32 [[X]], [[LOOP_BACKEDGETAKENCOUNT]], [[DBG59]]
; ALL-NEXT: call void @llvm.dbg.value(metadata i1 [[X_CURR_ISBITUNSET]], [[META57:metadata !.*]], metadata !DIExpression()), [[DBG62]] ; LZCNT-NEXT: [[X_NEXT:%.*]] = shl i32 [[X]], [[LOOP_TRIPCOUNT]], [[DBG59]]
; ALL-NEXT: [[X_NEXT]] = shl i32 [[X_CURR]], 1, [[DBG63:!dbg !.*]] ; LZCNT-NEXT: br label [[LOOP:%.*]], [[DBG60:!dbg !.*]]
; ALL-NEXT: call void @llvm.dbg.value(metadata i32 [[X_NEXT]], [[META58:metadata !.*]], metadata !DIExpression()), [[DBG63]] ; LZCNT: loop:
; ALL-NEXT: br i1 [[X_CURR_ISBITUNSET]], label [[LOOP]], label [[END:%.*]], [[DBG64:!dbg !.*]] ; LZCNT-NEXT: [[TMP0:%.*]] = phi i32 [ [[X]], [[ENTRY:%.*]] ], [ [[X_NEXT]], [[LOOP]] ], [[DBG59]]
; ALL: end: ; LZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR]], [[META55:metadata !.*]], metadata !DIExpression()), [[DBG59]]
; ALL-NEXT: [[X_CURR_LCSSA:%.*]] = phi i32 [ [[X_CURR]], [[LOOP]] ], [[DBG60]] ; LZCNT-NEXT: [[X_CURR_BITMASKED:%.*]] = and i32 [[X_CURR]], 32768, [[DBG61:!dbg !.*]]
; ALL-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_LCSSA]], [[META55]], metadata !DIExpression()), [[DBG60]] ; LZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_BITMASKED]], [[META56:metadata !.*]], metadata !DIExpression()), [[DBG61]]
; ALL-NEXT: ret i32 [[X_CURR_LCSSA]], [[DBG65:!dbg !.*]] ; LZCNT-NEXT: [[X_CURR_ISBITUNSET:%.*]] = icmp eq i32 [[X_CURR_BITMASKED]], 0, [[DBG62:!dbg !.*]]
; LZCNT-NEXT: call void @llvm.dbg.value(metadata i1 [[X_CURR_ISBITUNSET]], [[META57:metadata !.*]], metadata !DIExpression()), [[DBG62]]
; LZCNT-NEXT: [[TMP1:%.*]] = shl i32 [[X_CURR]], 1, [[DBG63:!dbg !.*]]
; LZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_NEXT]], [[META58:metadata !.*]], metadata !DIExpression()), [[DBG63]]
; LZCNT-NEXT: br i1 true, label [[END:%.*]], label [[LOOP]], [[DBG64:!dbg !.*]]
; LZCNT: end:
; LZCNT-NEXT: [[X_CURR_LCSSA:%.*]] = phi i32 [ [[X_CURR]], [[LOOP]] ], [[DBG59]]
; LZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_LCSSA]], [[META55]], metadata !DIExpression()), [[DBG59]]
; LZCNT-NEXT: ret i32 [[X_CURR_LCSSA]], [[DBG65:!dbg !.*]]
;
; NOLZCNT-LABEL: @p3_constant_mask_15thbit(
; NOLZCNT-NEXT: entry:
; NOLZCNT-NEXT: br label [[LOOP:%.*]], [[DBG59:!dbg !.*]]
; NOLZCNT: loop:
; NOLZCNT-NEXT: [[X_CURR:%.*]] = phi i32 [ [[X:%.*]], [[ENTRY:%.*]] ], [ [[X_NEXT:%.*]], [[LOOP]] ], [[DBG60:!dbg !.*]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR]], [[META55:metadata !.*]], metadata !DIExpression()), [[DBG60]]
; NOLZCNT-NEXT: [[X_CURR_BITMASKED:%.*]] = and i32 [[X_CURR]], 32768, [[DBG61:!dbg !.*]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_BITMASKED]], [[META56:metadata !.*]], metadata !DIExpression()), [[DBG61]]
; NOLZCNT-NEXT: [[X_CURR_ISBITUNSET:%.*]] = icmp eq i32 [[X_CURR_BITMASKED]], 0, [[DBG62:!dbg !.*]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i1 [[X_CURR_ISBITUNSET]], [[META57:metadata !.*]], metadata !DIExpression()), [[DBG62]]
; NOLZCNT-NEXT: [[X_NEXT]] = shl i32 [[X_CURR]], 1, [[DBG63:!dbg !.*]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_NEXT]], [[META58:metadata !.*]], metadata !DIExpression()), [[DBG63]]
; NOLZCNT-NEXT: br i1 [[X_CURR_ISBITUNSET]], label [[LOOP]], label [[END:%.*]], [[DBG64:!dbg !.*]]
; NOLZCNT: end:
; NOLZCNT-NEXT: [[X_CURR_LCSSA:%.*]] = phi i32 [ [[X_CURR]], [[LOOP]] ], [[DBG60]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_LCSSA]], [[META55]], metadata !DIExpression()), [[DBG60]]
; NOLZCNT-NEXT: ret i32 [[X_CURR_LCSSA]], [[DBG65:!dbg !.*]]
; ;
entry: entry:
br label %loop br label %loop
loop: loop:
%x.curr = phi i32 [ %x, %entry ], [ %x.next, %loop ] %x.curr = phi i32 [ %x, %entry ], [ %x.next, %loop ]
%x.curr.bitmasked = and i32 %x.curr, 32768 %x.curr.bitmasked = and i32 %x.curr, 32768
%x.curr.isbitunset = icmp eq i32 %x.curr.bitmasked, 0 %x.curr.isbitunset = icmp eq i32 %x.curr.bitmasked, 0
▲ Show 20 Lines • Show All 139 Lines • ▼ Show 20 Lines
end: end:
store i32 %x.curr, i32* %p0 store i32 %x.curr, i32* %p0
store i32 %x.next, i32* %p1 store i32 %x.next, i32* %p1
ret void ret void
} }
define i32 @p6_constant_mask_signbit_noncanonical(i32 %x) { define i32 @p6_constant_mask_signbit_noncanonical(i32 %x) {
; ALL-LABEL: @p6_constant_mask_signbit_noncanonical( ; LZCNT-LABEL: @p6_constant_mask_signbit_noncanonical(
; ALL-NEXT: entry: ; LZCNT-NEXT: entry:
; ALL-NEXT: br label [[LOOP:%.*]], [[DBG104:!dbg !.*]] ; LZCNT-NEXT: [[X_NUMLEADINGZEROS:%.*]] = call i32 @llvm.ctlz.i32(i32 [[X:%.*]], i1 true), [[DBG104:!dbg !.*]]
; ALL: loop: ; LZCNT-NEXT: [[X_NUMACTIVEBITS:%.*]] = sub i32 32, [[X_NUMLEADINGZEROS]], [[DBG104]]
; ALL-NEXT: [[X_CURR:%.*]] = phi i32 [ [[X:%.*]], [[ENTRY:%.*]] ], [ [[X_NEXT:%.*]], [[LOOP]] ], [[DBG105:!dbg !.*]] ; LZCNT-NEXT: [[X_NUMLEADINGONEPOS:%.*]] = add i32 [[X_NUMACTIVEBITS]], -1, [[DBG104]]
; ALL-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR]], [[META100:metadata !.*]], metadata !DIExpression()), [[DBG105]] ; LZCNT-NEXT: [[LOOP_BACKEDGETAKENCOUNT:%.*]] = sub i32 31, [[X_NUMLEADINGONEPOS]], [[DBG104]]
; ALL-NEXT: [[X_CURR_BITMASKED:%.*]] = and i32 [[X_CURR]], -2147483648, [[DBG106:!dbg !.*]] ; LZCNT-NEXT: [[LOOP_TRIPCOUNT:%.*]] = add nuw i32 [[LOOP_BACKEDGETAKENCOUNT]], 1, [[DBG104]]
; ALL-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_BITMASKED]], [[META101:metadata !.*]], metadata !DIExpression()), [[DBG106]] ; LZCNT-NEXT: [[X_CURR:%.*]] = shl i32 [[X]], [[LOOP_BACKEDGETAKENCOUNT]], [[DBG104]]
; ALL-NEXT: [[X_CURR_ISBITUNSET:%.*]] = icmp eq i32 [[X_CURR_BITMASKED]], 0, [[DBG107:!dbg !.*]] ; LZCNT-NEXT: [[X_NEXT:%.*]] = shl i32 [[X]], [[LOOP_TRIPCOUNT]], [[DBG104]]
; ALL-NEXT: call void @llvm.dbg.value(metadata i1 [[X_CURR_ISBITUNSET]], [[META102:metadata !.*]], metadata !DIExpression()), [[DBG107]] ; LZCNT-NEXT: br label [[LOOP:%.*]], [[DBG105:!dbg !.*]]
; ALL-NEXT: [[X_NEXT]] = shl i32 [[X_CURR]], 1, [[DBG108:!dbg !.*]] ; LZCNT: loop:
; ALL-NEXT: call void @llvm.dbg.value(metadata i32 [[X_NEXT]], [[META103:metadata !.*]], metadata !DIExpression()), [[DBG108]] ; LZCNT-NEXT: [[TMP0:%.*]] = phi i32 [ [[X]], [[ENTRY:%.*]] ], [ [[X_NEXT]], [[LOOP]] ], [[DBG104]]
; ALL-NEXT: br i1 [[X_CURR_ISBITUNSET]], label [[LOOP]], label [[END:%.*]], [[DBG109:!dbg !.*]] ; LZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR]], [[META100:metadata !.*]], metadata !DIExpression()), [[DBG104]]
; ALL: end: ; LZCNT-NEXT: [[X_CURR_BITMASKED:%.*]] = and i32 [[X_CURR]], -2147483648, [[DBG106:!dbg !.*]]
; ALL-NEXT: [[X_CURR_LCSSA:%.*]] = phi i32 [ [[X_CURR]], [[LOOP]] ], [[DBG105]] ; LZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_BITMASKED]], [[META101:metadata !.*]], metadata !DIExpression()), [[DBG106]]
; ALL-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_LCSSA]], [[META100]], metadata !DIExpression()), [[DBG105]] ; LZCNT-NEXT: [[X_CURR_ISBITUNSET:%.*]] = icmp eq i32 [[X_CURR_BITMASKED]], 0, [[DBG107:!dbg !.*]]
; ALL-NEXT: ret i32 [[X_CURR_LCSSA]], [[DBG110:!dbg !.*]] ; LZCNT-NEXT: call void @llvm.dbg.value(metadata i1 [[X_CURR_ISBITUNSET]], [[META102:metadata !.*]], metadata !DIExpression()), [[DBG107]]
; LZCNT-NEXT: [[TMP1:%.*]] = shl i32 [[X_CURR]], 1, [[DBG108:!dbg !.*]]
; LZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_NEXT]], [[META103:metadata !.*]], metadata !DIExpression()), [[DBG108]]
; LZCNT-NEXT: br i1 true, label [[END:%.*]], label [[LOOP]], [[DBG109:!dbg !.*]]
; LZCNT: end:
; LZCNT-NEXT: [[X_CURR_LCSSA:%.*]] = phi i32 [ [[X_CURR]], [[LOOP]] ], [[DBG104]]
; LZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_LCSSA]], [[META100]], metadata !DIExpression()), [[DBG104]]
; LZCNT-NEXT: ret i32 [[X_CURR_LCSSA]], [[DBG110:!dbg !.*]]
;
; NOLZCNT-LABEL: @p6_constant_mask_signbit_noncanonical(
; NOLZCNT-NEXT: entry:
; NOLZCNT-NEXT: br label [[LOOP:%.*]], [[DBG104:!dbg !.*]]
; NOLZCNT: loop:
; NOLZCNT-NEXT: [[X_CURR:%.*]] = phi i32 [ [[X:%.*]], [[ENTRY:%.*]] ], [ [[X_NEXT:%.*]], [[LOOP]] ], [[DBG105:!dbg !.*]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR]], [[META100:metadata !.*]], metadata !DIExpression()), [[DBG105]]
; NOLZCNT-NEXT: [[X_CURR_BITMASKED:%.*]] = and i32 [[X_CURR]], -2147483648, [[DBG106:!dbg !.*]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_BITMASKED]], [[META101:metadata !.*]], metadata !DIExpression()), [[DBG106]]
; NOLZCNT-NEXT: [[X_CURR_ISBITUNSET:%.*]] = icmp eq i32 [[X_CURR_BITMASKED]], 0, [[DBG107:!dbg !.*]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i1 [[X_CURR_ISBITUNSET]], [[META102:metadata !.*]], metadata !DIExpression()), [[DBG107]]
; NOLZCNT-NEXT: [[X_NEXT]] = shl i32 [[X_CURR]], 1, [[DBG108:!dbg !.*]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_NEXT]], [[META103:metadata !.*]], metadata !DIExpression()), [[DBG108]]
; NOLZCNT-NEXT: br i1 [[X_CURR_ISBITUNSET]], label [[LOOP]], label [[END:%.*]], [[DBG109:!dbg !.*]]
; NOLZCNT: end:
; NOLZCNT-NEXT: [[X_CURR_LCSSA:%.*]] = phi i32 [ [[X_CURR]], [[LOOP]] ], [[DBG105]]
; NOLZCNT-NEXT: call void @llvm.dbg.value(metadata i32 [[X_CURR_LCSSA]], [[META100]], metadata !DIExpression()), [[DBG105]]
; NOLZCNT-NEXT: ret i32 [[X_CURR_LCSSA]], [[DBG110:!dbg !.*]]
; ;
entry: entry:
br label %loop br label %loop
loop: loop:
%x.curr = phi i32 [ %x, %entry ], [ %x.next, %loop ] %x.curr = phi i32 [ %x, %entry ], [ %x.next, %loop ]
%x.curr.bitmasked = and i32 %x.curr, 2147483648 %x.curr.bitmasked = and i32 %x.curr, 2147483648
%x.curr.isbitunset = icmp eq i32 %x.curr.bitmasked, 0 %x.curr.isbitunset = icmp eq i32 %x.curr.bitmasked, 0
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