Fix SpeculativelyExecuteBB to either speculate all or none of the phis

present in the bottom of the CFG triangle, as the transformation isn't
ever valuable if the branch can't be eliminated.

Also, unify some heuristics between SimplifyCFG's multiple
if-converters, for consistency.

This fixes rdar://10627242.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147630 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 55 insertions, 6 deletions

diff --git a/test/Transforms/SimplifyCFG/2009-01-19-UnconditionalTrappingConstantExpr.ll b/test/Transforms/SimplifyCFG/2009-01-19-UnconditionalTrappingConstantExpr.ll
index 568e61c6ac..e2765e5f50 100644
--- a/test/Transforms/SimplifyCFG/2009-01-19-UnconditionalTrappingConstantExpr.ll
+++ b/test/Transforms/SimplifyCFG/2009-01-19-UnconditionalTrappingConstantExpr.ll
@@ -1,9 +1,14 @@
-; RUN: opt < %s -simplifycfg -S | grep {br i1 } | count 4
+; RUN: opt < %s -simplifycfg -S | FileCheck %s
 ; PR3354
 ; Do not merge bb1 into the entry block, it might trap.
 
 @G = extern_weak global i32
 
+; CHECK: @test(
+; CHECK: br i1 %tmp25
+; CHECK: bb1:
+; CHECK: sdiv
+
 define i32 @test(i32 %tmp21, i32 %tmp24) {
 	%tmp25 = icmp sle i32 %tmp21, %tmp24		
 	br i1 %tmp25, label %bb2, label %bb1	
@@ -18,6 +23,11 @@ bb6:
 	ret i32 927
 }
 
+; CHECK: @test2(
+; CHECK: br i1 %tmp34
+; CHECK: bb5:
+; CHECK: sdiv
+
 define i32 @test2(i32 %tmp21, i32 %tmp24, i1 %tmp34) {
 	br i1 %tmp34, label %bb5, label %bb6
 
diff --git a/test/Transforms/SimplifyCFG/multiple-phis.ll b/test/Transforms/SimplifyCFG/multiple-phis.ll
new file mode 100644
index 0000000000..7845423246
--- /dev/null
+++ b/test/Transforms/SimplifyCFG/multiple-phis.ll
@@ -0,0 +1,39 @@
+; RUN: opt -simplifycfg -S < %s | FileCheck %s
+
+; It's not worthwhile to if-convert one of the phi nodes and leave
+; the other behind, because that still requires a branch. If
+; SimplifyCFG if-converts one of the phis, it should do both.
+
+; CHECK:      %div.high.addr.0 = select i1 %cmp1, i32 %div, i32 %high.addr.0
+; CHECK-NEXT: %low.0.add2 = select i1 %cmp1, i32 %low.0, i32 %add2
+; CHECK-NEXT: br label %while.cond
+
+define i32 @upper_bound(i32* %r, i32 %high, i32 %k) nounwind {
+entry:
+  br label %while.cond
+
+while.cond:                                       ; preds = %if.then, %if.else, %entry
+  %high.addr.0 = phi i32 [ %high, %entry ], [ %div, %if.then ], [ %high.addr.0, %if.else ]
+  %low.0 = phi i32 [ 0, %entry ], [ %low.0, %if.then ], [ %add2, %if.else ]
+  %cmp = icmp ult i32 %low.0, %high.addr.0
+  br i1 %cmp, label %while.body, label %while.end
+
+while.body:                                       ; preds = %while.cond
+  %add = add i32 %low.0, %high.addr.0
+  %div = udiv i32 %add, 2
+  %idxprom = zext i32 %div to i64
+  %arrayidx = getelementptr inbounds i32* %r, i64 %idxprom
+  %0 = load i32* %arrayidx
+  %cmp1 = icmp ult i32 %k, %0
+  br i1 %cmp1, label %if.then, label %if.else
+
+if.then:                                          ; preds = %while.body
+  br label %while.cond
+
+if.else:                                          ; preds = %while.body
+  %add2 = add i32 %div, 1
+  br label %while.cond
+
+while.end:                                        ; preds = %while.cond
+  ret i32 %low.0
+}
diff --git a/test/Transforms/SimplifyCFG/select-gep.ll b/test/Transforms/SimplifyCFG/select-gep.ll
index 009f05e557..7654d0271a 100644
--- a/test/Transforms/SimplifyCFG/select-gep.ll
+++ b/test/Transforms/SimplifyCFG/select-gep.ll
@@ -35,6 +35,6 @@ if.end:
   ret i8* %x.addr
 
 ; CHECK: @test2
-; CHECK: %x.addr = select i1 %cmp, i8* %incdec.ptr, i8* %y
-; CHECK: ret i8* %x.addr
+; CHECK: %incdec.ptr.y = select i1 %cmp, i8* %incdec.ptr, i8* %y
+; CHECK: ret i8* %incdec.ptr.y
 }
diff --git a/test/Transforms/SimplifyCFG/switch-masked-bits.ll b/test/Transforms/SimplifyCFG/switch-masked-bits.ll
index fc83ec2078..3b0c48be6e 100644
--- a/test/Transforms/SimplifyCFG/switch-masked-bits.ll
+++ b/test/Transforms/SimplifyCFG/switch-masked-bits.ll
@@ -15,8 +15,8 @@ c:
   ret i32 5
 ; CHECK: @test1
 ; CHECK: %cond = icmp eq i32 %i, 24
-; CHECK: %merge = select i1 %cond, i32 5, i32 0
-; CHECK: ret i32 %merge
+; CHECK: %. = select i1 %cond, i32 5, i32 0
+; CHECK: ret i32 %.
 }
 
 
diff --git a/test/Transforms/SimplifyCFG/switch-on-const-select.ll b/test/Transforms/SimplifyCFG/switch-on-const-select.ll
index 5494a651d4..673a62bf03 100644
--- a/test/Transforms/SimplifyCFG/switch-on-const-select.ll
+++ b/test/Transforms/SimplifyCFG/switch-on-const-select.ll
@@ -115,7 +115,7 @@ entry:
 cont:
 ; CHECK: %lt = icmp slt i64 %x, %y
     %lt = icmp slt i64 %x, %y
-; CHECK-NEXT: br i1 %lt, label %a, label %r
+; CHECK-NEXT: select i1 %lt, i32 -1, i32 1
     %qux = select i1 %lt, i32 0, i32 2
     switch i32 %qux, label %bees [
         i32 0, label %a