maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[ARM] Ignore GEPs in ARMCodeGenPrepare 

While searching through the use-def tree, ignore GetElementPtrInst
instructions because they don't need promoting and neither do their
indices. Otherwise, the wide indices prevent the transformation from
happening.

Differential Revision: https://reviews.llvm.org/D50762

llvm-svn: 339871
This commit is contained in:
Sam Parker 2018-08-16 12:24:40 +00:00
parent 7f2df7df45
commit 0d51197051
2 changed files with 56 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
llvm/lib/Target/ARM/ARMCodeGenPrepare.cpp
View File

@ -582,6 +582,11 @@ bool ARMCodeGenPrepare::TryToPromote(Value *V) {
if (CurrentVisited.count(V))
return true;
// Ignore GEPs because they don't need promoting and the constant indices
// will prevent the transformation.
if (isa<GetElementPtrInst>(V))
return true;
if (!isSupportedValue(V) || (shouldPromote(V) && !isLegalToPromote(V))) {
LLVM_DEBUG(dbgs() << "ARM CGP: Can't handle: " << *V << "\n");
return false;

51
llvm/test/CodeGen/ARM/arm-cgp-pointers.ll
View File

@ -82,3 +82,54 @@ entry:
%res = select i1 %cmp, i16 128, i16 255
ret i16 %res
}
; CHECK-LABEL: gep_2d_array
; CHECK-NOT: uxt
define i8 @gep_2d_array(i8** %a, i8 zeroext %arg) {
entry:
%arrayidx.us = getelementptr inbounds i8*, i8** %a, i32 0
%0 = load i8*, i8** %arrayidx.us, align 4
%1 = load i8, i8* %0, align 1
%sub = sub nuw i8 %1, 1
%cmp = icmp ult i8 %sub, %arg
%res = select i1 %cmp, i8 27, i8 54
ret i8 %res
}
; CHECK-LABEL: gep_2d_array_loop
; CHECK-NOT: uxt
define void @gep_2d_array_loop(i16** nocapture readonly %a, i16** nocapture readonly %b, i32 %N) {
entry:
%cmp30 = icmp eq i32 %N, 0
br i1 %cmp30, label %for.cond.cleanup, label %for.cond1.preheader.us
for.cond1.preheader.us:
%y.031.us = phi i32 [ %inc13.us, %for.cond1.for.cond.cleanup3_crit_edge.us ], [ 0, %entry ]
br label %for.body4.us
for.body4.us:
%x.029.us = phi i32 [ 0, %for.cond1.preheader.us ], [ %inc.us, %for.body4.us ]
%arrayidx.us = getelementptr inbounds i16*, i16** %a, i32 %x.029.us
%0 = load i16*, i16** %arrayidx.us, align 4
%arrayidx5.us = getelementptr inbounds i16, i16* %0, i32 %y.031.us
%1 = load i16, i16* %arrayidx5.us, align 2
%dec.us = add nuw i16 %1, -1
%cmp6.us = icmp ult i16 %dec.us, 16383
%shl.us = shl nuw i16 %dec.us, 2
%spec.select.us = select i1 %cmp6.us, i16 %shl.us, i16 %dec.us
%arrayidx10.us = getelementptr inbounds i16*, i16** %b, i32 %x.029.us
%2 = load i16*, i16** %arrayidx10.us, align 4
%arrayidx11.us = getelementptr inbounds i16, i16* %2, i32 %y.031.us
store i16 %spec.select.us, i16* %arrayidx11.us, align 2
%inc.us = add nuw i32 %x.029.us, 1
%exitcond = icmp eq i32 %inc.us, %N
br i1 %exitcond, label %for.cond1.for.cond.cleanup3_crit_edge.us, label %for.body4.us
for.cond1.for.cond.cleanup3_crit_edge.us:
%inc13.us = add nuw i32 %y.031.us, 1
%exitcond32 = icmp eq i32 %inc13.us, %N
br i1 %exitcond32, label %for.cond.cleanup, label %for.cond1.preheader.us
for.cond.cleanup:
ret void
}