[PATCH] D108965: [RISCV] Add a test case showing an extra sext.w near a sh2add with multiple uses. NFC
Craig Topper via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Wed Sep 1 11:06:55 PDT 2021
This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rGaf1ca4353e83: [RISCV] Add a test case showing an extra sext.w near a sh2add with multiple… (authored by craig.topper).
Changed prior to commit:
https://reviews.llvm.org/D108965?vs=369609&id=369996#toc
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D108965/new/
https://reviews.llvm.org/D108965
Files:
llvm/test/CodeGen/RISCV/rv64zba.ll
Index: llvm/test/CodeGen/RISCV/rv64zba.ll
===================================================================
--- llvm/test/CodeGen/RISCV/rv64zba.ll
+++ llvm/test/CodeGen/RISCV/rv64zba.ll
@@ -371,6 +371,49 @@
ret i64 %5
}
+; Type legalization inserts a sext_inreg after the first add. That add will be
+; selected as sh2add which does not sign extend. SimplifyDemandedBits is unable
+; to remove the sext_inreg because it has multiple uses. The ashr will use the
+; sext_inreg to become sraiw. This leaves the sext_inreg only used by the shl.
+; If the shl is selected as sllw, we don't need the sext_inreg.
+; FIXME: We should not emit a sext.w.
+define i64 @sh2add_extra_sext(i32 %x, i32 %y, i32 %z) {
+; RV64I-LABEL: sh2add_extra_sext:
+; RV64I: # %bb.0:
+; RV64I-NEXT: slliw a0, a0, 2
+; RV64I-NEXT: addw a0, a0, a1
+; RV64I-NEXT: sllw a1, a2, a0
+; RV64I-NEXT: sraiw a0, a0, 2
+; RV64I-NEXT: mul a0, a1, a0
+; RV64I-NEXT: ret
+;
+; RV64B-LABEL: sh2add_extra_sext:
+; RV64B: # %bb.0:
+; RV64B-NEXT: sh2add a0, a0, a1
+; RV64B-NEXT: sext.w a1, a0
+; RV64B-NEXT: sllw a1, a2, a1
+; RV64B-NEXT: sraiw a0, a0, 2
+; RV64B-NEXT: mul a0, a1, a0
+; RV64B-NEXT: ret
+;
+; RV64ZBA-LABEL: sh2add_extra_sext:
+; RV64ZBA: # %bb.0:
+; RV64ZBA-NEXT: sh2add a0, a0, a1
+; RV64ZBA-NEXT: sext.w a1, a0
+; RV64ZBA-NEXT: sllw a1, a2, a1
+; RV64ZBA-NEXT: sraiw a0, a0, 2
+; RV64ZBA-NEXT: mul a0, a1, a0
+; RV64ZBA-NEXT: ret
+ %a = shl i32 %x, 2
+ %b = add i32 %a, %y
+ %c = shl i32 %z, %b
+ %d = ashr i32 %b, 2
+ %e = sext i32 %c to i64
+ %f = sext i32 %d to i64
+ %g = mul i64 %e, %f
+ ret i64 %g
+}
+
define i64 @addmul6(i64 %a, i64 %b) {
; RV64I-LABEL: addmul6:
; RV64I: # %bb.0:
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