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[ForwardOpTree] Support hoisted invariant loads. 

Hoisted loads can be trivially supported because there are no
MemoryAccess to be modified, the loaded value is just available
at code generation.

llvm-svn: 308826
This commit is contained in:
Michael Kruse 2017-07-22 14:30:02 +00:00
parent a6b2de3b59
commit e5f4706a55
2 changed files with 65 additions and 5 deletions
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6
polly/lib/Transform/ForwardOpTree.cpp
View File

@ -120,6 +120,7 @@ private:
switch (VUse.getKind()) {
case VirtualUse::Constant:
case VirtualUse::Block:
case VirtualUse::Hoisted:
// These can be used anywhere without special considerations.
if (DoIt)
return FD_DidForward;
@ -130,11 +131,6 @@ private:
DEBUG(dbgs() << " Cannot forward synthesizable: " << *UseVal << "\n");
return FD_CannotForward;
case VirtualUse::Hoisted:
// Not supported yet.
DEBUG(dbgs() << " Cannot forward hoisted load: " << *UseVal << "\n");
return FD_CannotForward;
case VirtualUse::ReadOnly:
// Not supported yet.
DEBUG(dbgs() << " Cannot forward read-only val: " << *UseVal << "\n");

64
polly/test/ForwardOpTree/forward_hoisted.ll Normal file
View File

@ -0,0 +1,64 @@
; RUN: opt %loadPolly -polly-invariant-load-hoisting=true -polly-optree -analyze < %s | FileCheck %s -match-full-lines
;
; Move %val to %bodyB, so %bodyA can be removed (by -polly-simplify)
;
; for (int j = 0; j < n; j += 1) {
; bodyA:
; double val = B[0] + 21.0;
;
; bodyB:
; A[0] = val;
; }
;
define void @func(i32 %n, double* noalias nonnull %A, double* noalias nonnull %B) {
entry:
br label %for
for:
%j = phi i32 [0, %entry], [%j.inc, %inc]
%j.cmp = icmp slt i32 %j, %n
br i1 %j.cmp, label %bodyA, label %exit
bodyA:
%val1 = load double, double* %B
%val2 = fadd double %val1, 21.0
br label %bodyB
bodyB:
store double %val2, double* %A
br label %inc
inc:
%j.inc = add nuw nsw i32 %j, 1
br label %for
exit:
br label %return
return:
ret void
}
; CHECK: Statistics {
; CHECK: Instructions copied: 1
; CHECK: Operand trees forwarded: 1
; CHECK: Statements with forwarded operand trees: 1
; CHECK: }
; CHECK: After statements {
; CHECK-NEXT: Stmt_bodyA
; CHECK-NEXT: MustWriteAccess := [Reduction Type: NONE] [Scalar: 1]
; CHECK-NEXT: [n] -> { Stmt_bodyA[i0] -> MemRef_val2[] };
; CHECK-NEXT: Instructions {
; CHECK-NEXT: %val1 = load double, double* %B
; CHECK-NEXT: %val2 = fadd double %val1, 2.100000e+01
; CHECK-NEXT: }
; CHECK-NEXT: Stmt_bodyB
; CHECK-NEXT: MustWriteAccess := [Reduction Type: NONE] [Scalar: 0]
; CHECK-NEXT: [n] -> { Stmt_bodyB[i0] -> MemRef_A[0] };
; CHECK-NEXT: Instructions {
; CHECK-NEXT: %val2 = fadd double %val1, 2.100000e+01
; CHECK-NEXT: store double %val2, double* %A
; CHECK-NEXT: }
; CHECK-NEXT: }