[llvm] ba5b015 - [InlineCost] CallAnalyzer: use TTI info for extractvalue - they are free (PR50099)

[Roman Lebedev via llvm-commits]

Author: Roman Lebedev
Date: 2021-04-30T13:55:11+03:00
New Revision: ba5b015b0de13b412d73d127ca181115c5e78717

URL: https://github.com/llvm/llvm-project/commit/ba5b015b0de13b412d73d127ca181115c5e78717
DIFF: https://github.com/llvm/llvm-project/commit/ba5b015b0de13b412d73d127ca181115c5e78717.diff

LOG: [InlineCost] CallAnalyzer: use TTI info for extractvalue - they are free (PR50099)

It seems incorrect to use TTI data in some places,
and override it in others. In this case, TTI says
that `extractvalue` are free, yet we bill them.

While this doesn't address https://bugs.llvm.org/show_bug.cgi?id=50099 yet,
it reduces the cost from 55 to 50 while the threshold is 45.

Differential Revision: https://reviews.llvm.org/D101228

Added: 
    

Modified: 
    llvm/lib/Analysis/InlineCost.cpp
    llvm/test/Transforms/Inline/X86/extractvalue.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/InlineCost.cpp b/llvm/lib/Analysis/InlineCost.cpp
index 9105813fad85d..91ac849f97b12 100644
--- a/llvm/lib/Analysis/InlineCost.cpp
+++ b/llvm/lib/Analysis/InlineCost.cpp
@@ -1759,8 +1759,8 @@ bool CallAnalyzer::visitExtractValue(ExtractValueInst &I) {
       }))
     return true;
 
-  // SROA can look through these but give them a cost.
-  return false;
+  // SROA can't look through these, but they may be free.
+  return Base::visitExtractValue(I);
 }
 
 bool CallAnalyzer::visitInsertValue(InsertValueInst &I) {
@@ -1772,8 +1772,8 @@ bool CallAnalyzer::visitInsertValue(InsertValueInst &I) {
       }))
     return true;
 
-  // SROA can look through these but give them a cost.
-  return false;
+  // SROA can't look through these, but they may be free.
+  return Base::visitInsertValue(I);
 }
 
 /// Try to simplify a call site.

diff  --git a/llvm/test/Transforms/Inline/X86/extractvalue.ll b/llvm/test/Transforms/Inline/X86/extractvalue.ll
index 1d1603a49a165..ad86def50e38a 100644
--- a/llvm/test/Transforms/Inline/X86/extractvalue.ll
+++ b/llvm/test/Transforms/Inline/X86/extractvalue.ll
@@ -9,9 +9,9 @@ target triple = "x86_64-unknown-unknown"
 
 ; CHECK: Analyzing call of callee... (caller:caller_range)
 ; CHECK-NEXT: define i32 @callee({ i32, i32 } %arg) {
-; CHECK-NEXT: ; cost before = -35, cost after = -30, threshold before = 0, threshold after = 0, cost delta = 5
+; CHECK-NEXT: ; cost before = -35, cost after = -35, threshold before = 0, threshold after = 0, cost delta = 0
 ; CHECK-NEXT:   %r = extractvalue { i32, i32 } %arg, 0
-; CHECK-NEXT: ; cost before = -30, cost after = -30, threshold before = 0, threshold after = 0, cost delta = 0
+; CHECK-NEXT: ; cost before = -35, cost after = -35, threshold before = 0, threshold after = 0, cost delta = 0
 ; CHECK-NEXT:   ret i32 %r
 ; CHECK-NEXT: }