http://llvm.org/bugs/show_bug.cgi?id=10267
Summary: instcombine deoptimizes testcase
Product: libraries
Version: trunk
Platform: PC
OS/Version: All
Status: NEW
Severity: normal
Priority: P
Component: Scalar Optimizations
AssignedTo: [email protected]
ReportedBy: [email protected]
CC: [email protected]
In the attached testcase, instcombine converts
%tmp2 = ptrtoint %struct.Shape* %tmp9 to i64
%and = and i64 %tmp2, -2
%tmp5 = inttoptr i64 %and to %struct.Shape*
%tobool = icmp ne %struct.Shape* %tmp5, null
br i1 %tobool, label %land.lhs.true, label %if.end
land.lhs.true: ; preds = %entry
%propid = getelementptr inbounds %struct.Shape* %tmp5, i32 0, i32 2
to
%tobool = icmp ugt %struct.Shape* %tmp9, inttoptr (i64 1 to %struct.Shape*)
br i1 %tobool, label %land.lhs.true, label %if.end
land.lhs.true: ; preds = %entry
%tmp2 = ptrtoint %struct.Shape* %tmp9 to i64
%and = and i64 %tmp2, -2
%tmp5 = inttoptr i64 %and to %struct.Shape*
%propid = getelementptr inbounds %struct.Shape* %tmp5, i64 0, i32 2
The first one produces:
movq (%rcx,%rax,8), %rdx
andq $-2, %rdx
je LBB0_3
## BB#1: ## %land.lhs.true
cmpq %rdi, 8(%rdx)
jne LBB0_3
The second one produces
movq (%rcx,%rax,8), %rdx
cmpq $2, %rdx
jb LBB0_3
## BB#1: ## %land.lhs.true
andq $-2, %rdx
cmpq %rdi, 8(%rdx)
jne LBB0_3
Note the extra "cmpq $2, %rdx"
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