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[CGP] Drop poison-generating flags after hoisting #90382

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merged 3 commits into from
Apr 29, 2024
Merged

[CGP] Drop poison-generating flags after hoisting #90382

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1c8e4bb
[CGP] Add pre-commit tests for PR90380. NFC.
dtcxzyw Apr 28, 2024
7e7bf0b
[CGP] Drop poison-generating flags in optimizeBranch
dtcxzyw Apr 28, 2024
e2130c4
[CGP] Add additional tests for ARM
dtcxzyw Apr 29, 2024
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2 changes: 2 additions & 0 deletions llvm/lib/CodeGen/CodeGenPrepare.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -8270,6 +8270,7 @@ static bool optimizeBranch(BranchInst *Branch, const TargetLowering &TLI,
IRBuilder<> Builder(Branch);
if (UI->getParent() != Branch->getParent())
UI->moveBefore(Branch);
UI->dropPoisonGeneratingFlags();
Value *NewCmp = Builder.CreateCmp(ICmpInst::ICMP_EQ, UI,
ConstantInt::get(UI->getType(), 0));
LLVM_DEBUG(dbgs() << "Converting " << *Cmp << "\n");
Expand All @@ -8283,6 +8284,7 @@ static bool optimizeBranch(BranchInst *Branch, const TargetLowering &TLI,
IRBuilder<> Builder(Branch);
if (UI->getParent() != Branch->getParent())
UI->moveBefore(Branch);
UI->dropPoisonGeneratingFlags();
Value *NewCmp = Builder.CreateCmp(Cmp->getPredicate(), UI,
ConstantInt::get(UI->getType(), 0));
LLVM_DEBUG(dbgs() << "Converting " << *Cmp << "\n");
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23 changes: 23 additions & 0 deletions llvm/test/Transforms/CodeGenPrepare/ARM/branch-on-zero.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -211,6 +211,29 @@ else:
ret i32 %l
}

define i32 @sub10_else_drop_nuw(i32 %a) {
; CHECK-LABEL: @sub10_else_drop_nuw(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[L:%.*]] = sub i32 [[A:%.*]], 10
; CHECK-NEXT: [[TMP0:%.*]] = icmp eq i32 [[L]], 0
; CHECK-NEXT: br i1 [[TMP0]], label [[THEN:%.*]], label [[ELSE:%.*]]
; CHECK: then:
; CHECK-NEXT: ret i32 0
; CHECK: else:
; CHECK-NEXT: ret i32 [[L]]
;
entry:
%c = icmp eq i32 %a, 10
br i1 %c, label %then, label %else

then:
ret i32 0

else:
%l = sub nuw i32 %a, 10
ret i32 %l
}

define i32 @subm10_then(i32 %a) {
; CHECK-LABEL: @subm10_then(
; CHECK-NEXT: entry:
Expand Down
80 changes: 80 additions & 0 deletions llvm/test/Transforms/CodeGenPrepare/RISCV/convert-to-eqz.ll
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@@ -0,0 +1,80 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
; RUN: opt -codegenprepare -S -mtriple=riscv64 < %s | FileCheck %s

define i8 @hoist_add(i8 %x) {
; CHECK-LABEL: define i8 @hoist_add(
; CHECK-SAME: i8 [[X:%.*]]) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[INC:%.*]] = add i8 [[X]], 1
; CHECK-NEXT: [[TMP0:%.*]] = icmp eq i8 [[INC]], 0
; CHECK-NEXT: br i1 [[TMP0]], label [[EXIT:%.*]], label [[IF_THEN:%.*]]
; CHECK: if.then:
; CHECK-NEXT: br label [[EXIT]]
; CHECK: exit:
; CHECK-NEXT: [[RETVAL:%.*]] = phi i8 [ [[INC]], [[IF_THEN]] ], [ -1, [[ENTRY:%.*]] ]
; CHECK-NEXT: ret i8 [[RETVAL]]
;
entry:
%cmp = icmp eq i8 %x, -1
br i1 %cmp, label %exit, label %if.then

if.then:
%inc = add nuw nsw i8 %x, 1
br label %exit

exit:
%retval = phi i8 [ %inc, %if.then ], [ -1, %entry ]
ret i8 %retval
}

define i8 @hoist_lshr(i8 %x) {
; CHECK-LABEL: define i8 @hoist_lshr(
; CHECK-SAME: i8 [[X:%.*]]) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[INC:%.*]] = lshr i8 [[X]], 3
; CHECK-NEXT: [[TMP0:%.*]] = icmp eq i8 [[INC]], 0
; CHECK-NEXT: br i1 [[TMP0]], label [[EXIT:%.*]], label [[IF_THEN:%.*]]
; CHECK: if.then:
; CHECK-NEXT: br label [[EXIT]]
; CHECK: exit:
; CHECK-NEXT: [[RETVAL:%.*]] = phi i8 [ [[INC]], [[IF_THEN]] ], [ -1, [[ENTRY:%.*]] ]
; CHECK-NEXT: ret i8 [[RETVAL]]
;
entry:
%cmp = icmp ult i8 %x, 8
br i1 %cmp, label %exit, label %if.then

if.then:
%inc = lshr exact i8 %x, 3
br label %exit

exit:
%retval = phi i8 [ %inc, %if.then ], [ -1, %entry ]
ret i8 %retval
}

define i8 @nomove_add(i8 %x) {
; CHECK-LABEL: define i8 @nomove_add(
; CHECK-SAME: i8 [[X:%.*]]) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[INC:%.*]] = add i8 [[X]], 1
; CHECK-NEXT: [[TMP0:%.*]] = icmp eq i8 [[INC]], 0
; CHECK-NEXT: br i1 [[TMP0]], label [[EXIT:%.*]], label [[IF_THEN:%.*]]
; CHECK: if.then:
; CHECK-NEXT: br label [[EXIT]]
; CHECK: exit:
; CHECK-NEXT: [[RETVAL:%.*]] = phi i8 [ [[INC]], [[IF_THEN]] ], [ -1, [[ENTRY:%.*]] ]
; CHECK-NEXT: ret i8 [[RETVAL]]
;
entry:
%inc = add nuw nsw i8 %x, 1
%cmp = icmp eq i8 %x, -1
br i1 %cmp, label %exit, label %if.then

if.then:
br label %exit

exit:
%retval = phi i8 [ %inc, %if.then ], [ -1, %entry ]
ret i8 %retval
}
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