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bf62cde86e
Previously, BranchProbabilityInfo::calcLoopBranchHeuristics would determine the weights of basic blocks inside loops even when it didn't have enough information to estimate the branch probabilities correctly. This patch fixes the function to exit early if it doesn't see any exit edges or back edges and let the later heuristics determine the weights. This fixes PR18705 and <rdar://problem/15991090>. Differential Revision: http://reviews.llvm.org/D3363 llvm-svn: 206194
59 lines
2.2 KiB
LLVM
59 lines
2.2 KiB
LLVM
; RUN: opt < %s -analyze -branch-prob | FileCheck %s
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; Since neither of while.body's out-edges is an exit or a back edge,
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; calcLoopBranchHeuristics should return early without setting the weights.
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; calcFloatingPointHeuristics, which is run later, sets the weights.
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;
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; CHECK: edge while.body -> if.then probability is 20 / 32 = 62.5%
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; CHECK: edge while.body -> if.else probability is 12 / 32 = 37.5%
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define void @foo1(i32 %n, i32* nocapture %b, i32* nocapture %c, i32* nocapture %d, float* nocapture readonly %f0, float* nocapture readonly %f1) {
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entry:
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%tobool8 = icmp eq i32 %n, 0
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br i1 %tobool8, label %while.end, label %while.body.lr.ph
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while.body.lr.ph:
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%0 = sext i32 %n to i64
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br label %while.body
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while.body:
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%indvars.iv = phi i64 [ %0, %while.body.lr.ph ], [ %indvars.iv.next, %if.end ]
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%b.addr.011 = phi i32* [ %b, %while.body.lr.ph ], [ %b.addr.1, %if.end ]
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%d.addr.010 = phi i32* [ %d, %while.body.lr.ph ], [ %incdec.ptr4, %if.end ]
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%c.addr.09 = phi i32* [ %c, %while.body.lr.ph ], [ %c.addr.1, %if.end ]
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%indvars.iv.next = add nsw i64 %indvars.iv, -1
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%arrayidx = getelementptr inbounds float* %f0, i64 %indvars.iv.next
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%1 = load float* %arrayidx, align 4
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%arrayidx2 = getelementptr inbounds float* %f1, i64 %indvars.iv.next
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%2 = load float* %arrayidx2, align 4
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%cmp = fcmp une float %1, %2
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br i1 %cmp, label %if.then, label %if.else
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if.then:
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%incdec.ptr = getelementptr inbounds i32* %b.addr.011, i64 1
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%3 = load i32* %b.addr.011, align 4
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%add = add nsw i32 %3, 12
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store i32 %add, i32* %b.addr.011, align 4
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br label %if.end
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if.else:
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%incdec.ptr3 = getelementptr inbounds i32* %c.addr.09, i64 1
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%4 = load i32* %c.addr.09, align 4
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%sub = add nsw i32 %4, -13
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store i32 %sub, i32* %c.addr.09, align 4
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br label %if.end
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if.end:
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%c.addr.1 = phi i32* [ %c.addr.09, %if.then ], [ %incdec.ptr3, %if.else ]
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%b.addr.1 = phi i32* [ %incdec.ptr, %if.then ], [ %b.addr.011, %if.else ]
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%incdec.ptr4 = getelementptr inbounds i32* %d.addr.010, i64 1
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store i32 14, i32* %d.addr.010, align 4
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%5 = trunc i64 %indvars.iv.next to i32
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%tobool = icmp eq i32 %5, 0
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br i1 %tobool, label %while.end, label %while.body
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while.end:
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ret void
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}
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