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[PassManager, SimplifyCFG] add test for PR34603 / D38566; NFC 

Sinking common insts and converting to select early can inhibit better folds in other passes.

llvm-svn: 316908
This commit is contained in:
Sanjay Patel 2017-10-30 14:34:30 +00:00
parent c928f2a6d4
commit 85b60ff68c
1 changed files with 41 additions and 1 deletions
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42
llvm/test/Transforms/PhaseOrdering/simplifycfg-options.ll
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@ -2,6 +2,8 @@
; RUN: opt -O1 -S < %s | FileCheck %s --check-prefix=ALL --check-prefix=OLDPM
; RUN: opt -passes='default<O1>' -S < %s | FileCheck %s --check-prefix=ALL --check-prefix=NEWPM
declare void @foo()
; Don't simplify unconditional branches from empty blocks in simplifyCFG
; until late in the pipeline because it can destroy canonical loop structure.
@ -62,5 +64,43 @@ if.end:
br label %for.cond
}
declare void @foo()
; PR34603 - https://bugs.llvm.org/show_bug.cgi?id=34603
; We should have a select of doubles, not a select of double pointers.
; SimplifyCFG should not flatten this before early-cse has a chance to eliminate redundant ops.
define double @max_of_loads(double* %x, double* %y, i64 %i) {
; ALL-LABEL: @max_of_loads(
; ALL-NEXT: entry:
; ALL-NEXT: [[XI_PTR:%.*]] = getelementptr double, double* [[X:%.*]], i64 [[I:%.*]]
; ALL-NEXT: [[YI_PTR:%.*]] = getelementptr double, double* [[Y:%.*]], i64 [[I]]
; ALL-NEXT: [[XI:%.*]] = load double, double* [[XI_PTR]], align 8
; ALL-NEXT: [[YI:%.*]] = load double, double* [[YI_PTR]], align 8
; ALL-NEXT: [[CMP:%.*]] = fcmp ogt double [[XI]], [[YI]]
; ALL-NEXT: [[Y_SINK:%.*]] = select i1 [[CMP]], double* [[X]], double* [[Y]]
; ALL-NEXT: [[YI_PTR_AGAIN:%.*]] = getelementptr double, double* [[Y_SINK]], i64 [[I]]
; ALL-NEXT: [[YI_AGAIN:%.*]] = load double, double* [[YI_PTR_AGAIN]], align 8
; ALL-NEXT: ret double [[YI_AGAIN]]
;
entry:
%xi_ptr = getelementptr double, double* %x, i64 %i
%yi_ptr = getelementptr double, double* %y, i64 %i
%xi = load double, double* %xi_ptr
%yi = load double, double* %yi_ptr
%cmp = fcmp ogt double %xi, %yi
br i1 %cmp, label %if, label %else
if:
%xi_ptr_again = getelementptr double, double* %x, i64 %i
%xi_again = load double, double* %xi_ptr_again
br label %end
else:
%yi_ptr_again = getelementptr double, double* %y, i64 %i
%yi_again = load double, double* %yi_ptr_again
br label %end
end:
%max = phi double [ %xi_again, %if ], [ %yi_again, %else ]
ret double %max
}